1
|
He L, Yang J, Hao Y, Yang X, Shi X, Zhang D, Zhao D, Yan W, Bie X, Chen L, Chen G, Zhao S, Liu X, Zheng H, Zhang K. DDX20: A Multifunctional Complex Protein. Molecules 2023; 28:7198. [PMID: 37894677 PMCID: PMC10608988 DOI: 10.3390/molecules28207198] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2023] [Revised: 09/18/2023] [Accepted: 09/28/2023] [Indexed: 10/29/2023] Open
Abstract
DEAD-box decapping enzyme 20 (DDX20) is a putative RNA-decapping enzyme that can be identified by the conserved motif Asp-Glu-Ala-Asp (DEAD). Cellular processes involve numerous RNA secondary structure alterations, including translation initiation, nuclear and mitochondrial splicing, and assembly of ribosomes and spliceosomes. DDX20 reportedly plays an important role in cellular transcription and post-transcriptional modifications. On the one hand, DDX20 can interact with various transcription factors and repress the transcriptional process. On the other hand, DDX20 forms the survival motor neuron complex and participates in the assembly of snRNP, ultimately affecting the RNA splicing process. Finally, DDX20 can potentially rely on its RNA-unwinding enzyme function to participate in microRNA (miRNA) maturation and act as a component of the RNA-induced silencing complex. In addition, although DDX20 is not a key component in the innate immune system signaling pathway, it can affect the nuclear factor kappa B (NF-κB) and p53 signaling pathways. In particular, DDX20 plays different roles in tumorigenesis development through the NF-κB signaling pathway. This process is regulated by various factors such as miRNA. DDX20 can influence processes such as viral replication in cells by interacting with two proteins in Epstein-Barr virus and can regulate the replication process of several viruses through the innate immune system, indicating that DDX20 plays an important role in the innate immune system. Herein, we review the effects of DDX20 on the innate immune system and its role in transcriptional and post-transcriptional modification processes, based on which we provide an outlook on the future of DDX20 research in innate immunity and viral infections.
Collapse
Affiliation(s)
- Lu He
- State Key Laboratory for Animal Disease Control and Prevention, College of Veterinary Medicine, Lanzhou University, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou 730000, China
- Gansu Province Research Center for Basic Disciplines of Pathogen Biology, Lanzhou 730046, China
| | - Jinke Yang
- State Key Laboratory for Animal Disease Control and Prevention, College of Veterinary Medicine, Lanzhou University, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou 730000, China
- Gansu Province Research Center for Basic Disciplines of Pathogen Biology, Lanzhou 730046, China
| | - Yu Hao
- State Key Laboratory for Animal Disease Control and Prevention, College of Veterinary Medicine, Lanzhou University, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou 730000, China
- Gansu Province Research Center for Basic Disciplines of Pathogen Biology, Lanzhou 730046, China
| | - Xing Yang
- State Key Laboratory for Animal Disease Control and Prevention, College of Veterinary Medicine, Lanzhou University, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou 730000, China
- Gansu Province Research Center for Basic Disciplines of Pathogen Biology, Lanzhou 730046, China
| | - Xijuan Shi
- State Key Laboratory for Animal Disease Control and Prevention, College of Veterinary Medicine, Lanzhou University, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou 730000, China
- Gansu Province Research Center for Basic Disciplines of Pathogen Biology, Lanzhou 730046, China
| | - Dajun Zhang
- State Key Laboratory for Animal Disease Control and Prevention, College of Veterinary Medicine, Lanzhou University, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou 730000, China
- Gansu Province Research Center for Basic Disciplines of Pathogen Biology, Lanzhou 730046, China
| | - Dengshuai Zhao
- State Key Laboratory for Animal Disease Control and Prevention, College of Veterinary Medicine, Lanzhou University, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou 730000, China
- Gansu Province Research Center for Basic Disciplines of Pathogen Biology, Lanzhou 730046, China
| | - Wenqian Yan
- State Key Laboratory for Animal Disease Control and Prevention, College of Veterinary Medicine, Lanzhou University, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou 730000, China
- Gansu Province Research Center for Basic Disciplines of Pathogen Biology, Lanzhou 730046, China
| | - Xintian Bie
- State Key Laboratory for Animal Disease Control and Prevention, College of Veterinary Medicine, Lanzhou University, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou 730000, China
- Gansu Province Research Center for Basic Disciplines of Pathogen Biology, Lanzhou 730046, China
| | - Lingling Chen
- State Key Laboratory for Animal Disease Control and Prevention, College of Veterinary Medicine, Lanzhou University, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou 730000, China
- Gansu Province Research Center for Basic Disciplines of Pathogen Biology, Lanzhou 730046, China
| | - Guohui Chen
- State Key Laboratory for Animal Disease Control and Prevention, College of Veterinary Medicine, Lanzhou University, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou 730000, China
- Gansu Province Research Center for Basic Disciplines of Pathogen Biology, Lanzhou 730046, China
| | - Siyue Zhao
- State Key Laboratory for Animal Disease Control and Prevention, College of Veterinary Medicine, Lanzhou University, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou 730000, China
- Gansu Province Research Center for Basic Disciplines of Pathogen Biology, Lanzhou 730046, China
| | - Xiangtao Liu
- State Key Laboratory for Animal Disease Control and Prevention, College of Veterinary Medicine, Lanzhou University, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou 730000, China
- Gansu Province Research Center for Basic Disciplines of Pathogen Biology, Lanzhou 730046, China
| | - Haixue Zheng
- State Key Laboratory for Animal Disease Control and Prevention, College of Veterinary Medicine, Lanzhou University, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou 730000, China
- Gansu Province Research Center for Basic Disciplines of Pathogen Biology, Lanzhou 730046, China
| | - Keshan Zhang
- State Key Laboratory for Animal Disease Control and Prevention, College of Veterinary Medicine, Lanzhou University, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou 730000, China
- Gansu Province Research Center for Basic Disciplines of Pathogen Biology, Lanzhou 730046, China
| |
Collapse
|
2
|
Pánek J, Roithová A, Radivojević N, Sýkora M, Prusty AB, Huston N, Wan H, Pyle AM, Fischer U, Staněk D. The SMN complex drives structural changes in human snRNAs to enable snRNP assembly. Nat Commun 2023; 14:6580. [PMID: 37852981 PMCID: PMC10584915 DOI: 10.1038/s41467-023-42324-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Accepted: 10/06/2023] [Indexed: 10/20/2023] Open
Abstract
Spliceosomal snRNPs are multicomponent particles that undergo a complex maturation pathway. Human Sm-class snRNAs are generated as 3'-end extended precursors, which are exported to the cytoplasm and assembled together with Sm proteins into core RNPs by the SMN complex. Here, we provide evidence that these pre-snRNA substrates contain compact, evolutionarily conserved secondary structures that overlap with the Sm binding site. These structural motifs in pre-snRNAs are predicted to interfere with Sm core assembly. We model structural rearrangements that lead to an open pre-snRNA conformation compatible with Sm protein interaction. The predicted rearrangement pathway is conserved in Metazoa and requires an external factor that initiates snRNA remodeling. We show that the essential helicase Gemin3, which is a component of the SMN complex, is crucial for snRNA structural rearrangements during snRNP maturation. The SMN complex thus facilitates ATP-driven structural changes in snRNAs that expose the Sm site and enable Sm protein binding.
Collapse
Affiliation(s)
- Josef Pánek
- Laboratory of Bioinformatics, Institute of Microbiology, Czech Academy of Sciences, Prague, Czech Republic.
| | - Adriana Roithová
- Laboratory of RNA Biology, Institute of Molecular Genetics, Czech Academy of Sciences, Prague, Czech Republic
- Laboratory of Regulation of Gene Expression, Institute of Microbiology, Czech Academy of Sciences, Prague, Czech Republic
| | - Nenad Radivojević
- Laboratory of RNA Biology, Institute of Molecular Genetics, Czech Academy of Sciences, Prague, Czech Republic
| | - Michal Sýkora
- Laboratory of RNA Biology, Institute of Molecular Genetics, Czech Academy of Sciences, Prague, Czech Republic
| | | | - Nicholas Huston
- Department of Molecular Biophysics & Biochemistry, Yale University, New Haven, USA
| | - Han Wan
- Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, USA
| | - Anna Marie Pyle
- Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, USA
- Department of Chemistry, Yale University, New Haven, USA
- Howard Hughes Medical Institute, Chevy Chase, USA
| | - Utz Fischer
- Department of Biochemistry, Theodor Boveri Institute, University of Würzburg, Würzburg, Germany
| | - David Staněk
- Laboratory of RNA Biology, Institute of Molecular Genetics, Czech Academy of Sciences, Prague, Czech Republic.
| |
Collapse
|
3
|
Hu Y, Hou Y, Zhou S, Wang Y, Shen C, Mu L, Su D, Zhang R. Mechanism of assembly of snRNP cores assisted by ICln and the SMN complex in fission yeast. iScience 2023; 26:107604. [PMID: 37664592 PMCID: PMC10470402 DOI: 10.1016/j.isci.2023.107604] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Revised: 07/11/2023] [Accepted: 08/08/2023] [Indexed: 09/05/2023] Open
Abstract
The spliceosomal snRNP cores, each comprised of a snRNA and a seven-membered Sm ring (D1/D2/F/E/G/D3/B), are assembled by twelve chaperoning proteins in human. However, only six assembly-assisting proteins, ICln and the SMN complex (SMN/Gemin2/Gemin6-8), have been found in Schizosaccharomyces pombe (Sp). Here, we used recombinant proteins to reconstitute the chaperone machinery and investigated the roles of these proteins systematically. We found that, like the human system, the assembly in S. pombe requires ICln and the SMN complex sequentially. However, there are several significant differences. For instance, h_F/E/G forms heterohexamers and heterotrimers, while Sp_F/E/G only forms heterohexamers; h_Gemin2 alone can bind D1/D2/F/E/G, but Sp_Gemin2 cannot. Moreover, we found that Sp_Gemin2 is essential using genetic approaches. These mechanistic studies reveal that these six proteins are necessary and sufficient for Sm core assembly at the molecular level, and enrich our understanding of the chaperone systems in species variation and evolution.
Collapse
Affiliation(s)
- Yan Hu
- Department of Ophthalmology, West China Hospital, Sichuan University and Collaborative Innovation Center for Biotherapy, Chengdu 610041, P.R. China
- State Key Laboratory of Biotherapy, West China Hospital, Sichuan University and Collaborative Innovation Center for Biotherapy, Chengdu 610041, P.R. China
| | - Yan Hou
- Department of Ophthalmology, West China Hospital, Sichuan University and Collaborative Innovation Center for Biotherapy, Chengdu 610041, P.R. China
- State Key Laboratory of Biotherapy, West China Hospital, Sichuan University and Collaborative Innovation Center for Biotherapy, Chengdu 610041, P.R. China
| | - Shijie Zhou
- Department of Ophthalmology, West China Hospital, Sichuan University and Collaborative Innovation Center for Biotherapy, Chengdu 610041, P.R. China
- State Key Laboratory of Biotherapy, West China Hospital, Sichuan University and Collaborative Innovation Center for Biotherapy, Chengdu 610041, P.R. China
| | - Yingzhi Wang
- Department of Ophthalmology, West China Hospital, Sichuan University and Collaborative Innovation Center for Biotherapy, Chengdu 610041, P.R. China
- State Key Laboratory of Biotherapy, West China Hospital, Sichuan University and Collaborative Innovation Center for Biotherapy, Chengdu 610041, P.R. China
| | - Congcong Shen
- Department of Ophthalmology, West China Hospital, Sichuan University and Collaborative Innovation Center for Biotherapy, Chengdu 610041, P.R. China
- State Key Laboratory of Biotherapy, West China Hospital, Sichuan University and Collaborative Innovation Center for Biotherapy, Chengdu 610041, P.R. China
| | - Li Mu
- Department of Ophthalmology, West China Hospital, Sichuan University and Collaborative Innovation Center for Biotherapy, Chengdu 610041, P.R. China
- State Key Laboratory of Biotherapy, West China Hospital, Sichuan University and Collaborative Innovation Center for Biotherapy, Chengdu 610041, P.R. China
| | - Dan Su
- State Key Laboratory of Biotherapy, West China Hospital, Sichuan University and Collaborative Innovation Center for Biotherapy, Chengdu 610041, P.R. China
| | - Rundong Zhang
- Department of Ophthalmology, West China Hospital, Sichuan University and Collaborative Innovation Center for Biotherapy, Chengdu 610041, P.R. China
- State Key Laboratory of Biotherapy, West China Hospital, Sichuan University and Collaborative Innovation Center for Biotherapy, Chengdu 610041, P.R. China
| |
Collapse
|
4
|
Zhang C, Guo Q, Chen L, Wu Z, Yan XJ, Zou C, Zhang Q, Tan J, Fang T, Rao Q, Li Y, Shen S, Deng M, Wang L, Gao H, Yu J, Li H, Zhang C, Nowsheen S, Kloeber J, Zhao F, Yin P, Teng C, Lin Z, Song K, Yao S, Yao L, Wu L, Zhang Y, Cheng X, Gao Q, Yuan J, Lou Z, Zhang JS. A ribosomal gene panel predicting a novel synthetic lethality in non-BRCAness tumors. Signal Transduct Target Ther 2023; 8:183. [PMID: 37160887 PMCID: PMC10170152 DOI: 10.1038/s41392-023-01401-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2022] [Revised: 02/04/2023] [Accepted: 02/27/2023] [Indexed: 05/11/2023] Open
Abstract
Poly (ADP-ribose) polymerase (PARP) inhibitors are one of the most exciting classes of targeted therapy agents for cancers with homologous recombination (HR) deficiency. However, many patients without apparent HR defects also respond well to PARP inhibitors/cisplatin. The biomarker responsible for this mechanism remains unclear. Here, we identified a set of ribosomal genes that predict response to PARP inhibitors/cisplatin in HR-proficient patients. PARP inhibitor/cisplatin selectively eliminates cells with high expression of the eight genes in the identified panel via DNA damage (ATM) signaling-induced pro-apoptotic ribosomal stress, which along with ATM signaling-induced pro-survival HR repair constitutes a new model to balance the cell fate in response to DNA damage. Therefore, the combined examination of the gene panel along with HR status would allow for more precise predictions of clinical response to PARP inhibitor/cisplatin. The gene panel as an independent biomarker was validated by multiple published clinical datasets, as well as by an ovarian cancer organoids library we established. More importantly, its predictive value was further verified in a cohort of PARP inhibitor-treated ovarian cancer patients with both RNA-seq and WGS data. Furthermore, we identified several marketed drugs capable of upregulating the expression of the genes in the panel without causing HR deficiency in PARP inhibitor/cisplatin-resistant cell lines. These drugs enhance PARP inhibitor/cisplatin sensitivity in both intrinsically resistant organoids and cell lines with acquired resistance. Together, our study identifies a marker gene panel for HR-proficient patients and reveals a broader application of PARP inhibitor/cisplatin in cancer therapy.
Collapse
Affiliation(s)
- Chao Zhang
- Beijing Institute of Basic Medical Sciences, 100850, Beijing, China
- Department of Oncology, Mayo Clinic, Rochester, MN, 55905, USA
| | - Qiang Guo
- School of Pharmaceutical Sciences, Wenzhou Medical University, 325035, Wenzhou, Zhejiang, China
| | - Lifeng Chen
- Key Laboratory of Endocrine Gland Diseases of Zhejiang Province, Zhejiang Provincial People's Hospital, 310014, Hangzhou, Zhejiang, China
- Department of Gynecology, Zhejiang Provincial People's Hospital, 310014, Hangzhou, Zhejiang, China
| | - Zheming Wu
- Department of Oncology, Mayo Clinic, Rochester, MN, 55905, USA
| | - Xiao-Jian Yan
- Department of Gynecology, the First Affiliated Hospital of Wenzhou Medical University, 325000, Wenzhou, Zhejiang, China
| | - Chengyang Zou
- Department of Gynecology, the First Affiliated Hospital of Wenzhou Medical University, 325000, Wenzhou, Zhejiang, China
| | - Qiuxue Zhang
- Wuhan Kingwise Biotechnology Co., Ltd., 430206, Wuhan, Hubei, China
| | - Jiahong Tan
- Cancer Biology Research Center (Key Laboratory of the Ministry of Education), Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, 430030, Wuhan, Hubei, China
| | - Tian Fang
- Cancer Biology Research Center (Key Laboratory of the Ministry of Education), Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, 430030, Wuhan, Hubei, China
| | - Qunxian Rao
- Department of Gynecological Oncology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, 510120, Guangzhou, Guangdong, China
| | - Yang Li
- Zhejiang Provincial Key Laboratory of Traditional Chinese Medicine for Reproductive Health Research, 310006, Hangzhou, Zhejiang, China
| | - Shizhen Shen
- Zhejiang Provincial Key Laboratory of Precision Diagnosis and Therapy for Major Gynecological Diseases, 310006, Hangzhou, Zhejiang, China
| | - Min Deng
- Department of Oncology, Mayo Clinic, Rochester, MN, 55905, USA
| | - Liewei Wang
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, MN, 55905, USA
| | - Huanyao Gao
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, MN, 55905, USA
| | - Jia Yu
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, MN, 55905, USA
| | - Hu Li
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, MN, 55905, USA
| | - Cheng Zhang
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, MN, 55905, USA
| | - Somaira Nowsheen
- Department of Dermatology, University of California San Diego, San Diego, CA, 92122, USA
| | - Jake Kloeber
- Department of Oncology, Mayo Clinic, Rochester, MN, 55905, USA
| | - Fei Zhao
- Department of Oncology, Mayo Clinic, Rochester, MN, 55905, USA
| | - Ping Yin
- Department of Oncology, Mayo Clinic, Rochester, MN, 55905, USA
| | - Chunbo Teng
- Key Laboratory of Saline-alkali Vegetation Ecology Restoration, Ministry of Education, College of Life Science, Northeast Forestry University, 150040, Harbin, China
| | - Zhongqiu Lin
- Department of Gynecological Oncology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, 510120, Guangzhou, Guangdong, China
| | - Kun Song
- Division of Gynecology Oncology, Department of Obstetrics and Gynecology, Qilu Hospital, Shandong University, 250012, Jinan, Shandong, China
| | - Shuzhong Yao
- Department of Obstetrics and Gynecology, the First Affiliated Hospital, Sun Yat-Sen University, 510080, Guangzhou, Guangdong, China
| | - Liangqing Yao
- Department of Gynecologic Oncology, Obstetrics and Gynecology Hospital of Fudan University, 200090, Shanghai, China
| | - Lingying Wu
- Department of Gynecologic Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, 100021, Beijing, China
| | - Yong Zhang
- Department of Radiation Oncology, Hubei Cancer Hospital, Tongji Medical College, Huazhong University of Science and Technology, 430030, Wuhan, Hubei, China
| | - Xiaodong Cheng
- Zhejiang Provincial Key Laboratory of Traditional Chinese Medicine for Reproductive Health Research, 310006, Hangzhou, Zhejiang, China.
- Department of Gynecologic Oncology, Women's Hospital, School of Medicine, Zhejiang University, 310006, Hangzhou, Zhejiang, China.
| | - Qinglei Gao
- Cancer Biology Research Center (Key Laboratory of the Ministry of Education), Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, 430030, Wuhan, Hubei, China.
| | - Jian Yuan
- Key Laboratory of Arrhythmias of the Ministry of Education of China, Research Center for Translational Medicine, East Hospital, Tongji University School of Medicine, 200120, Shanghai, China.
- Department of Biochemistry and Molecular Biology, Tongji University School of Medicine, 200120, Shanghai, China.
| | - Zhenkun Lou
- Department of Oncology, Mayo Clinic, Rochester, MN, 55905, USA.
| | - Jin-San Zhang
- The Quzhou Affiliated Hospital of Wenzhou Medical University, Quzhou People's Hospital, 324000, Quzhou, Zhejiang, China.
- Medical Research Center, and Key Laboratory of Interventional Pulmonology of Zhejiang Province, The First Affiliated Hospital of Wenzhou Medical University, 325000, Wenzhou, Zhejiang, China.
| |
Collapse
|
5
|
Kowalczyk M, Kowalczyk E, Gogolewska M, Skrzypek M, Talarowska M, Majsterek I, Poplawski T, Kwiatkowski P, Sienkiewicz M. Association of polymorphic variants in GEMIN genes with the risk of depression in a Polish population. PeerJ 2022; 10:e14317. [PMID: 36405016 PMCID: PMC9673762 DOI: 10.7717/peerj.14317] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Accepted: 10/09/2022] [Indexed: 11/16/2022] Open
Abstract
Background The role of miRNA in depression is widely described by many researchers. miRNA is a final product of many genes involved in its formation (maturation). One of the final steps in the formation of miRNAs is the formation of the RISC complex, called the RNA-induced silencing complex, which includes, among others, GEMIN proteins. Single-nucleotide polymorphisms (SNPs) may lead to disturbance of miRNA biogenesis and function. The objective of our research was to assess the relationship between the appearance of depression and single nucleotide polymorphisms in the GEMIN3 (rs197388) and GEMIN4 (rs7813; rs3744741) genes. Our research provides new knowledge on the genetic factors that influence the risk of depression. They can be used as an element of diagnostics helpful in identifying people at increased risk, as well as indicating people not at risk of depression. Methods A total of 218 participants were examined, including individuals with depressive disorders (n = 102; study group) and healthy people (n = 116, control group). All the patients in the study group and the people in the control group were non-related native Caucasian Poles from central Poland. Blood was collected from study and control groups in order to assess the SNPs of GEMIN genes. Results An analysis of the results obtained showed that in patient population, the risk of depression is almost doubled by polymorphic variants of the genes: rs197388/GEMIN3 genotype A/A in the recessive model and rs3744741/GEMIN4 genotype T/T, codominant and recessive model. The dual role of rs7813/GEMIN4 is noteworthy, where the G/A genotype in the codominant and over dominant model protects against depression.
Collapse
Affiliation(s)
| | - Edward Kowalczyk
- Department of Pharmacology and Toxicology, Medical University of Lodz, Lodz, Poland
| | - Monika Gogolewska
- Department of Clinical Chemistry and Biochemistry, Medical University of Lodz, Lodz, Poland
| | - Maciej Skrzypek
- Department of Clinical Chemistry and Biochemistry, Medical University of Lodz, Lodz, Poland
| | - Monika Talarowska
- Department of Clinical Psychology and Psychopathology, University of Lodz, Lodz, Poland
| | - Ireneusz Majsterek
- Department of Clinical Chemistry and Biochemistry, Medical University of Lodz, Lodz, Poland
| | - Tomasz Poplawski
- Department of Microbiology and Pharmaceutical Biochemistry, Medical University of Lodz, Lodz, Poland
| | - Paweł Kwiatkowski
- Department of Diagnostic Immunology, Pomeranian Medical University in Szczecin, Szczecin, Poland
| | - Monika Sienkiewicz
- Department of Pharmaceutical Microbiology and Microbiological Diagnostic, Medical University of Lodz, Lodz, Poland
| |
Collapse
|
6
|
Altassan R, Qudair A, Alokaili R, Alhasan K, Faqeih EA, Alhashem A, Alowain M, Alsayed M, Rahbeeni Z, Albadi L, Alkuraya FS, Anderson EN, Rajan D, Pandey UB. Further delineation of GEMIN4 related neurodevelopmental disorder with microcephaly, cataract, and renal abnormalities syndrome. Am J Med Genet A 2022; 188:2932-2940. [PMID: 35861185 DOI: 10.1002/ajmg.a.62894] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2022] [Revised: 06/21/2022] [Accepted: 06/27/2022] [Indexed: 01/31/2023]
Abstract
Pathogenic variants in GEMIN4 have recently been linked to an inherited autosomal recessive neurodevelopmental disorder characterized with microcephaly, cataracts, and renal abnormalities (NEDMCR syndrome). This report provides a retrospective review of 16 patients from 11 unrelated Saudi consanguineous families with GEMIN4 mutations. The cohort comprises 11 new and unpublished clinical details from five previously described patients. Only two missense, homozygous, pathogenic variants were found in all affected patients, suggesting a founder effect. All patients shared global developmental delay with variable ophthalmological, renal, and skeletal manifestations. In addition, we knocked down endogenous Drosophila GEMIN4 in neurons to further investigate the mechanism of the functional defects in affected patients. Our fly model findings demonstrated developmental defects and motor dysfunction suggesting that loss of GEMIN4 function is detrimental in vivo; likely similar to human patients. To date, this study presents the largest cohort of patients affected with GEMIN4 mutations. Considering that identifying GEMIN4 defects in patients presenting with neurodevelopmental delay and congenital cataract will help in early diagnosis, appropriate management and prevention plans that can be made for affected families.
Collapse
Affiliation(s)
- Ruqaiah Altassan
- Department of Medical Genetics, Centre for Genomic Medicine, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia.,Department of Anatomy and Cell Biology, College of Medicine, Alfaisal University, Riyadh, Saudi Arabia
| | - Ahmad Qudair
- Department of Medical Genetics, Centre for Genomic Medicine, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - Riyadh Alokaili
- Department of Radiology, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - Khalid Alhasan
- Department of Pediatrics, College of Medicine, King Saud University, Riyadh, Saudi Arabia.,Department of Pediatrics, King Saud University Medical City, Riyadh, Saudi Arabia
| | - Eissa A Faqeih
- Medical Genetics Section, King Fahad Medical City, Children's Hospital, Riyadh, Kingdom of Saudi Arabia
| | - Amal Alhashem
- Division of Genetics, Department of Pediatrics, Prince Sultan Military Medical City, Riyadh, Saudi Arabia
| | - Muhammed Alowain
- Department of Medical Genetics, Centre for Genomic Medicine, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia.,Department of Anatomy and Cell Biology, College of Medicine, Alfaisal University, Riyadh, Saudi Arabia
| | - Moeanaldeen Alsayed
- Department of Medical Genetics, Centre for Genomic Medicine, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia.,Department of Anatomy and Cell Biology, College of Medicine, Alfaisal University, Riyadh, Saudi Arabia
| | - Zuhair Rahbeeni
- Department of Medical Genetics, Centre for Genomic Medicine, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - Lama Albadi
- Department of Translational Genomics, Centre for Genomic Medicine, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - Fowzan S Alkuraya
- Department of Translational Genomics, Centre for Genomic Medicine, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - Eric N Anderson
- Department of Pediatrics, Children's Hospital of Pittsburgh, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, USA
| | - Deepa Rajan
- Department of Pediatrics, Children's Hospital of Pittsburgh, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, USA
| | - Udai Bhan Pandey
- Department of Pediatrics, Children's Hospital of Pittsburgh, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, USA
| |
Collapse
|
7
|
López-Cortés A, Echeverría-Garcés G, Ramos-Medina MJ. Molecular Pathogenesis and New Therapeutic Dimensions for Spinal Muscular Atrophy. BIOLOGY 2022; 11:biology11060894. [PMID: 35741415 PMCID: PMC9219894 DOI: 10.3390/biology11060894] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Revised: 05/04/2022] [Accepted: 05/06/2022] [Indexed: 11/16/2022]
Abstract
The condition known as 5q spinal muscular atrophy (SMA) is a devastating autosomal recessive neuromuscular disease caused by a deficiency of the ubiquitous protein survival of motor neuron (SMN), which is encoded by the SMN1 and SMN2 genes. It is one of the most common pediatric recessive genetic diseases, and it represents the most common cause of hereditary infant mortality. After decades of intensive basic and clinical research efforts, and improvements in the standard of care, successful therapeutic milestones have been developed, delaying the progression of 5q SMA and increasing patient survival. At the same time, promising data from early-stage clinical trials have indicated that additional therapeutic options are likely to emerge in the near future. Here, we provide updated information on the molecular underpinnings of SMA; we also provide an overview of the rapidly evolving therapeutic landscape for SMA, including SMN-targeted therapies, SMN-independent therapies, and combinational therapies that are likely to be key for the development of treatments that are effective across a patient’s lifespan.
Collapse
Affiliation(s)
- Andrés López-Cortés
- Programa de Investigación en Salud Global, Facultad de Ciencias de la Salud, Universidad Internacional SEK, Quito 170302, Ecuador
- Facultad de Medicina, Universidad de Las Américas, Quito 170124, Ecuador
- Latin American Network for the Implementation and Validation of Clinical Pharmacogenomics Guidelines (RELIVAF-CYTED), 28001 Madrid, Spain; (G.E.-G.); (M.J.R.-M.)
- Correspondence:
| | - Gabriela Echeverría-Garcés
- Latin American Network for the Implementation and Validation of Clinical Pharmacogenomics Guidelines (RELIVAF-CYTED), 28001 Madrid, Spain; (G.E.-G.); (M.J.R.-M.)
| | - María José Ramos-Medina
- Latin American Network for the Implementation and Validation of Clinical Pharmacogenomics Guidelines (RELIVAF-CYTED), 28001 Madrid, Spain; (G.E.-G.); (M.J.R.-M.)
| |
Collapse
|
8
|
Jacquier V, Prévot M, Gostan T, Bordonné R, Benkhelifa-Ziyyat S, Barkats M, Soret J. Splicing efficiency of minor introns in a mouse model of SMA predominantly depends on their branchpoint sequence and can involve the contribution of major spliceosome components. RNA (NEW YORK, N.Y.) 2022; 28:303-319. [PMID: 34893560 PMCID: PMC8848931 DOI: 10.1261/rna.078329.120] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Accepted: 11/22/2021] [Indexed: 06/14/2023]
Abstract
Spinal muscular atrophy (SMA) is a devastating neurodegenerative disease caused by reduced amounts of the ubiquitously expressed Survival of Motor Neuron (SMN) protein. In agreement with its crucial role in the biogenesis of spliceosomal snRNPs, SMN-deficiency is correlated to numerous splicing alterations in patient cells and various tissues of SMA mouse models. Among the snRNPs whose assembly is impacted by SMN-deficiency, those involved in the minor spliceosome are particularly affected. Importantly, splicing of several, but not all U12-dependent introns has been shown to be affected in different SMA models. Here, we have investigated the molecular determinants of this differential splicing in spinal cords from SMA mice. We show that the branchpoint sequence (BPS) is a key element controlling splicing efficiency of minor introns. Unexpectedly, splicing of several minor introns with suboptimal BPS is not affected in SMA mice. Using in vitro splicing experiments and oligonucleotides targeting minor or major snRNAs, we show for the first time that splicing of these introns involves both the minor and major machineries. Our results strongly suggest that splicing of a subset of minor introns is not affected in SMA mice because components of the major spliceosome compensate for the loss of minor splicing activity.
Collapse
Affiliation(s)
- Valentin Jacquier
- Institut de Génétique Moléculaire de Montpellier, Univ Montpellier, CNRS, Montpellier 34293, France
| | - Manon Prévot
- Institut de Génétique Moléculaire de Montpellier, Univ Montpellier, CNRS, Montpellier 34293, France
| | - Thierry Gostan
- Institut de Génétique Moléculaire de Montpellier, Univ Montpellier, CNRS, Montpellier 34293, France
| | - Rémy Bordonné
- Institut de Génétique Moléculaire de Montpellier, Univ Montpellier, CNRS, Montpellier 34293, France
| | - Sofia Benkhelifa-Ziyyat
- Centre de Recherche en Myologie (CRM), Institut de Myologie, Sorbonne Universités, UPMC Univ Paris 06, Inserm UMRS974, GH Pitié Salpêtrière, Paris 75013, France
| | - Martine Barkats
- Centre de Recherche en Myologie (CRM), Institut de Myologie, Sorbonne Universités, UPMC Univ Paris 06, Inserm UMRS974, GH Pitié Salpêtrière, Paris 75013, France
| | - Johann Soret
- Institut de Génétique Moléculaire de Montpellier, Univ Montpellier, CNRS, Montpellier 34293, France
| |
Collapse
|
9
|
Aldhalaan H, AlBakheet A, AlRuways S, AlMutairi N, AlNakiyah M, AlGhofaili R, Cardona-Londoño KJ, Alahmadi KO, AlQudairy H, AlRasheed MM, Colak D, Arold ST, Kaya N. A Novel GEMIN4 Variant in a Consanguineous Family Leads to Neurodevelopmental Impairment with Severe Microcephaly, Spastic Quadriplegia, Epilepsy, and Cataracts. Genes (Basel) 2021; 13:genes13010092. [PMID: 35052432 PMCID: PMC8774908 DOI: 10.3390/genes13010092] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2021] [Revised: 12/24/2021] [Accepted: 12/25/2021] [Indexed: 12/24/2022] Open
Abstract
Pathogenic variants in GEMIN4 contribute to a hereditary disorder characterized by neurodevelopmental features, microcephaly, cataracts, and renal abnormalities (known as NEDMCR). To date, only two homoallelic variations have been linked to the disease. Moreover, clinical features associated with the variants have not been fully elucidated yet. Here, we identified a novel variant in GEMIN4 (NM_015721:exon2:c.440A>G:p.His147Arg) in two siblings from a consanguineous Saudi family by using whole exome sequencing followed by Sanger sequence verification. We comprehensively investigated the patients’ clinical features, including brain imaging and electroencephalogram findings, and compared their phenotypic characteristics with those of previously reported cases. In silico prediction and structural modeling support that the p.His147Arg variant is pathogenic.
Collapse
Affiliation(s)
- Hesham Aldhalaan
- Neurosciences Department, King Faisal Specialist Hospital and Research Centre, Riyadh 11211, Saudi Arabia;
| | - Albandary AlBakheet
- Translational Genomic Department, Center for Genomic Medicine, King Faisal Specialist Hospital and Research Centre, Riyadh 11211, Saudi Arabia; (A.A.); (S.A.); (N.A.); (M.A.); (R.A.); (H.A.)
| | - Sarah AlRuways
- Translational Genomic Department, Center for Genomic Medicine, King Faisal Specialist Hospital and Research Centre, Riyadh 11211, Saudi Arabia; (A.A.); (S.A.); (N.A.); (M.A.); (R.A.); (H.A.)
- Clinical Pharmacy Department, College of Pharmacy, King Saud University, Riyadh 11211, Saudi Arabia;
| | - Nouf AlMutairi
- Translational Genomic Department, Center for Genomic Medicine, King Faisal Specialist Hospital and Research Centre, Riyadh 11211, Saudi Arabia; (A.A.); (S.A.); (N.A.); (M.A.); (R.A.); (H.A.)
- Clinical Pharmacy Department, College of Pharmacy, King Saud University, Riyadh 11211, Saudi Arabia;
| | - Maha AlNakiyah
- Translational Genomic Department, Center for Genomic Medicine, King Faisal Specialist Hospital and Research Centre, Riyadh 11211, Saudi Arabia; (A.A.); (S.A.); (N.A.); (M.A.); (R.A.); (H.A.)
- Clinical Pharmacy Department, College of Pharmacy, King Saud University, Riyadh 11211, Saudi Arabia;
| | - Reema AlGhofaili
- Translational Genomic Department, Center for Genomic Medicine, King Faisal Specialist Hospital and Research Centre, Riyadh 11211, Saudi Arabia; (A.A.); (S.A.); (N.A.); (M.A.); (R.A.); (H.A.)
- Clinical Pharmacy Department, College of Pharmacy, King Saud University, Riyadh 11211, Saudi Arabia;
| | - Kelly J. Cardona-Londoño
- Division of Biological and Environmental Sciences and Engineering (BESE), Computational Bioscience Research Center (CBRC), King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia; (K.J.C.-L.); (S.T.A.)
| | - Khalid Omar Alahmadi
- Department of Radiology, King Faisal Specialist Hospital and Research Centre, Riyadh 11211, Saudi Arabia;
| | - Hanan AlQudairy
- Translational Genomic Department, Center for Genomic Medicine, King Faisal Specialist Hospital and Research Centre, Riyadh 11211, Saudi Arabia; (A.A.); (S.A.); (N.A.); (M.A.); (R.A.); (H.A.)
| | - Maha M. AlRasheed
- Clinical Pharmacy Department, College of Pharmacy, King Saud University, Riyadh 11211, Saudi Arabia;
| | - Dilek Colak
- Department of Biostatistics, Epidemiology and Scientific Computing, King Faisal Specialist Hospital and Research Centre, Riyadh 11211, Saudi Arabia;
| | - Stefan T. Arold
- Division of Biological and Environmental Sciences and Engineering (BESE), Computational Bioscience Research Center (CBRC), King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia; (K.J.C.-L.); (S.T.A.)
| | - Namik Kaya
- Translational Genomic Department, Center for Genomic Medicine, King Faisal Specialist Hospital and Research Centre, Riyadh 11211, Saudi Arabia; (A.A.); (S.A.); (N.A.); (M.A.); (R.A.); (H.A.)
- Correspondence: ; Tel.: +966-11-4647272 (ext. 39612)
| |
Collapse
|
10
|
Blatnik AJ, McGovern VL, Burghes AHM. What Genetics Has Told Us and How It Can Inform Future Experiments for Spinal Muscular Atrophy, a Perspective. Int J Mol Sci 2021; 22:8494. [PMID: 34445199 PMCID: PMC8395208 DOI: 10.3390/ijms22168494] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Revised: 07/28/2021] [Accepted: 08/04/2021] [Indexed: 02/06/2023] Open
Abstract
Proximal spinal muscular atrophy (SMA) is an autosomal recessive neurodegenerative disorder characterized by motor neuron loss and subsequent atrophy of skeletal muscle. SMA is caused by deficiency of the essential survival motor neuron (SMN) protein, canonically responsible for the assembly of the spliceosomal small nuclear ribonucleoproteins (snRNPs). Therapeutics aimed at increasing SMN protein levels are efficacious in treating SMA. However, it remains unknown how deficiency of SMN results in motor neuron loss, resulting in many reported cellular functions of SMN and pathways affected in SMA. Herein is a perspective detailing what genetics and biochemistry have told us about SMA and SMN, from identifying the SMA determinant region of the genome, to the development of therapeutics. Furthermore, we will discuss how genetics and biochemistry have been used to understand SMN function and how we can determine which of these are critical to SMA moving forward.
Collapse
Affiliation(s)
| | | | - Arthur H. M. Burghes
- Department of Biological Chemistry & Pharmacology, The Ohio State University Wexner Medical Center, Rightmire Hall, Room 168, 1060 Carmack Road, Columbus, OH 43210, USA; (A.J.B.III); (V.L.M.)
| |
Collapse
|
11
|
In Search of a Cure: The Development of Therapeutics to Alter the Progression of Spinal Muscular Atrophy. Brain Sci 2021; 11:brainsci11020194. [PMID: 33562482 PMCID: PMC7915832 DOI: 10.3390/brainsci11020194] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Revised: 01/29/2021] [Accepted: 02/01/2021] [Indexed: 12/19/2022] Open
Abstract
Until the recent development of disease-modifying therapeutics, spinal muscular atrophy (SMA) was considered a devastating neuromuscular disease with a poor prognosis for most affected individuals. Symptoms generally present during early childhood and manifest as muscle weakness and progressive paralysis, severely compromising the affected individual’s quality of life, independence, and lifespan. SMA is most commonly caused by the inheritance of homozygously deleted SMN1 alleles with retention of one or more copies of a paralog gene, SMN2, which inversely correlates with disease severity. The recent advent and use of genetically targeted therapies have transformed SMA into a prototype for monogenic disease treatment in the era of genetic medicine. Many SMA-affected individuals receiving these therapies achieve traditionally unobtainable motor milestones and survival rates as medicines drastically alter the natural progression of this disease. This review discusses historical SMA progression and underlying disease mechanisms, highlights advances made in therapeutic research, clinical trials, and FDA-approved medicines, and discusses possible second-generation and complementary medicines as well as optimal temporal intervention windows in order to optimize motor function and improve quality of life for all SMA-affected individuals.
Collapse
|
12
|
Yi H, Mu L, Shen C, Kong X, Wang Y, Hou Y, Zhang R. Negative cooperativity between Gemin2 and RNA provides insights into RNA selection and the SMN complex's release in snRNP assembly. Nucleic Acids Res 2020; 48:895-911. [PMID: 31799625 PMCID: PMC6954390 DOI: 10.1093/nar/gkz1135] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Revised: 11/14/2019] [Accepted: 11/21/2019] [Indexed: 02/05/2023] Open
Abstract
The assembly of snRNP cores, in which seven Sm proteins, D1/D2/F/E/G/D3/B, form a ring around the nonameric Sm site of snRNAs, is the early step of spliceosome formation and essential to eukaryotes. It is mediated by the PMRT5 and SMN complexes sequentially in vivo. SMN deficiency causes neurodegenerative disease spinal muscular atrophy (SMA). How the SMN complex assembles snRNP cores is largely unknown, especially how the SMN complex achieves high RNA assembly specificity and how it is released. Here we show, using crystallographic and biochemical approaches, that Gemin2 of the SMN complex enhances RNA specificity of SmD1/D2/F/E/G via a negative cooperativity between Gemin2 and RNA in binding SmD1/D2/F/E/G. Gemin2, independent of its N-tail, constrains the horseshoe-shaped SmD1/D2/F/E/G from outside in a physiologically relevant, narrow state, enabling high RNA specificity. Moreover, the assembly of RNAs inside widens SmD1/D2/F/E/G, causes the release of Gemin2/SMN allosterically and allows SmD3/B to join. The assembly of SmD3/B further facilitates the release of Gemin2/SMN. This is the first to show negative cooperativity in snRNP assembly, which provides insights into RNA selection and the SMN complex's release. These findings reveal a basic mechanism of snRNP core assembly and facilitate pathogenesis studies of SMA.
Collapse
Affiliation(s)
- Hongfei Yi
- Department of Ophthalmology, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University and Collaborative Innovation Center for Biotherapy, Chengdu 610041, P.R. China
| | - Li Mu
- Department of Ophthalmology, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University and Collaborative Innovation Center for Biotherapy, Chengdu 610041, P.R. China
| | - Congcong Shen
- Department of Ophthalmology, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University and Collaborative Innovation Center for Biotherapy, Chengdu 610041, P.R. China
| | - Xi Kong
- Department of Ophthalmology, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University and Collaborative Innovation Center for Biotherapy, Chengdu 610041, P.R. China
| | - Yingzhi Wang
- Department of Ophthalmology, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University and Collaborative Innovation Center for Biotherapy, Chengdu 610041, P.R. China
| | - Yan Hou
- Department of Ophthalmology, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University and Collaborative Innovation Center for Biotherapy, Chengdu 610041, P.R. China
| | - Rundong Zhang
- Department of Ophthalmology, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University and Collaborative Innovation Center for Biotherapy, Chengdu 610041, P.R. China
| |
Collapse
|
13
|
Li X, Wang X, Cheng Z, Zhu Q. AGO2 and its partners: a silencing complex, a chromatin modulator, and new features. Crit Rev Biochem Mol Biol 2020; 55:33-53. [DOI: 10.1080/10409238.2020.1738331] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- Xiaojing Li
- Xiangya School of Pharmaceutical Sciences, Central South University, Changsha, Hunan, China
| | - Xueying Wang
- Xiangya School of Pharmaceutical Sciences, Central South University, Changsha, Hunan, China
| | - Zeneng Cheng
- Xiangya School of Pharmaceutical Sciences, Central South University, Changsha, Hunan, China
| | - Qubo Zhu
- Xiangya School of Pharmaceutical Sciences, Central South University, Changsha, Hunan, China
| |
Collapse
|
14
|
Cacciottolo R, Ciantar J, Lanfranco M, Borg RM, Vassallo N, Bordonné R, Cauchi RJ. SMN complex member Gemin3 self-interacts and has a functional relationship with ALS-linked proteins TDP-43, FUS and Sod1. Sci Rep 2019; 9:18666. [PMID: 31822699 PMCID: PMC6904755 DOI: 10.1038/s41598-019-53508-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Accepted: 10/29/2019] [Indexed: 02/07/2023] Open
Abstract
The predominant motor neuron disease in infants and adults is spinal muscular atrophy (SMA) and amyotrophic lateral sclerosis (ALS), respectively. SMA is caused by insufficient levels of the Survival Motor Neuron (SMN) protein, which operates as part of the multiprotein SMN complex that includes the DEAD-box RNA helicase Gemin3/DDX20/DP103. C9orf72, SOD1, TDP-43 and FUS are ranked as the four major genes causing familial ALS. Accumulating evidence has revealed a surprising molecular overlap between SMA and ALS. Here, we ask the question of whether Drosophila can also be exploited to study shared pathogenic pathways. Focusing on motor behaviour, muscle mass and survival, we show that disruption of either TBPH/TDP-43 or Caz/FUS enhance defects associated with Gemin3 loss-of-function. Gemin3-associated neuromuscular junction overgrowth was however suppressed. Sod1 depletion had a modifying effect in late adulthood. We also show that Gemin3 self-interacts and Gem3ΔN, a helicase domain deletion mutant, retains the ability to interact with its wild-type counterpart. Importantly, mutant:wild-type dimers are favoured more than wild-type:wild-type dimers. In addition to reinforcing the link between SMA and ALS, further exploration of mechanistic overlaps is now possible in a genetically tractable model organism. Notably, Gemin3 can be elevated to a candidate for modifying motor neuron degeneration.
Collapse
Affiliation(s)
- Rebecca Cacciottolo
- Institut de Génétique Moléculaire de Montpellier, CNRS-UMR 5535, Université de Montpellier, Montpellier, France.,Department of Physiology and Biochemistry, Faculty of Medicine and Surgery, University of Malta, Msida, Malta.,Centre for Molecular Medicine and Biobanking, Biomedical Sciences Building, University of Malta, Msida, Malta
| | - Joanna Ciantar
- Department of Physiology and Biochemistry, Faculty of Medicine and Surgery, University of Malta, Msida, Malta.,Centre for Molecular Medicine and Biobanking, Biomedical Sciences Building, University of Malta, Msida, Malta
| | - Maia Lanfranco
- Institut de Génétique Moléculaire de Montpellier, CNRS-UMR 5535, Université de Montpellier, Montpellier, France.,Department of Physiology and Biochemistry, Faculty of Medicine and Surgery, University of Malta, Msida, Malta.,Centre for Molecular Medicine and Biobanking, Biomedical Sciences Building, University of Malta, Msida, Malta
| | - Rebecca M Borg
- Institut de Génétique Moléculaire de Montpellier, CNRS-UMR 5535, Université de Montpellier, Montpellier, France.,Department of Physiology and Biochemistry, Faculty of Medicine and Surgery, University of Malta, Msida, Malta.,Centre for Molecular Medicine and Biobanking, Biomedical Sciences Building, University of Malta, Msida, Malta
| | - Neville Vassallo
- Department of Physiology and Biochemistry, Faculty of Medicine and Surgery, University of Malta, Msida, Malta.,Centre for Molecular Medicine and Biobanking, Biomedical Sciences Building, University of Malta, Msida, Malta
| | - Rémy Bordonné
- Institut de Génétique Moléculaire de Montpellier, CNRS-UMR 5535, Université de Montpellier, Montpellier, France
| | - Ruben J Cauchi
- Department of Physiology and Biochemistry, Faculty of Medicine and Surgery, University of Malta, Msida, Malta. .,Centre for Molecular Medicine and Biobanking, Biomedical Sciences Building, University of Malta, Msida, Malta.
| |
Collapse
|
15
|
Massenet S. In vivo assembly of eukaryotic signal recognition particle: A still enigmatic process involving the SMN complex. Biochimie 2019; 164:99-104. [PMID: 30978374 DOI: 10.1016/j.biochi.2019.04.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Accepted: 04/07/2019] [Indexed: 12/29/2022]
Abstract
The signal recognition particle (SRP) is a universally conserved non-coding ribonucleoprotein complex that is essential for targeting transmembrane and secretory proteins to the endoplasmic reticulum. Its composition and size varied during evolution. In mammals, SRP contains one RNA molecule, 7SL RNA, and six proteins: SRP9, 14, 19, 54, 68 and 72. Despite a very good understanding of the SRP structure and of the SRP assembly in vitro, how SRP is assembled in vivo remains largely enigmatic. Here we review current knowledge on how the 7SL RNA is assembled with core proteins to form functional RNP particles in cells. SRP biogenesis is believed to take place both in the nucleolus and in the cytoplasm and to rely on the survival of motor neuron complex, whose defect leads to spinal muscular atrophy.
Collapse
Affiliation(s)
- Séverine Massenet
- Ingénierie Moléculaire et Physiopathologie Articulaire, UMR 7365 CNRS-University of Lorraine, Biopôle de l'Université de Lorraine, Campus Brabois-Santé, 9 avenue de la forêt de Haye, BP 20199, 54505 Vandoeuvre-les-Nancy, France.
| |
Collapse
|
16
|
Composition of the Survival Motor Neuron (SMN) Complex in Drosophila melanogaster. G3-GENES GENOMES GENETICS 2019; 9:491-503. [PMID: 30563832 PMCID: PMC6385987 DOI: 10.1534/g3.118.200874] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Spinal Muscular Atrophy (SMA) is caused by homozygous mutations in the human survival motor neuron 1 (SMN1) gene. SMN protein has a well-characterized role in the biogenesis of small nuclear ribonucleoproteins (snRNPs), core components of the spliceosome. SMN is part of an oligomeric complex with core binding partners, collectively called Gemins. Biochemical and cell biological studies demonstrate that certain Gemins are required for proper snRNP assembly and transport. However, the precise functions of most Gemins are unknown. To gain a deeper understanding of the SMN complex in the context of metazoan evolution, we investigated its composition in Drosophila melanogaster Using transgenic flies that exclusively express Flag-tagged SMN from its native promoter, we previously found that Gemin2, Gemin3, Gemin5, and all nine classical Sm proteins, including Lsm10 and Lsm11, co-purify with SMN. Here, we show that CG2941 is also highly enriched in the pulldown. Reciprocal co-immunoprecipitation reveals that epitope-tagged CG2941 interacts with endogenous SMN in Schneider2 cells. Bioinformatic comparisons show that CG2941 shares sequence and structural similarity with metazoan Gemin4. Additional analysis shows that three other genes (CG14164, CG31950 and CG2371) are not orthologous to Gemins 6-7-8, respectively, as previously suggested. In D.melanogaster, CG2941 is located within an evolutionarily recent genomic triplication with two other nearly identical paralogous genes (CG32783 and CG32786). RNAi-mediated knockdown of CG2941 and its two close paralogs reveals that Gemin4 is essential for organismal viability.
Collapse
|
17
|
Mertsch S, Schlicht K, Melkonyan H, Schlatt S, Thanos S. snRPN controls the ability of neurons to regenerate axons. Restor Neurol Neurosci 2018; 36:31-43. [PMID: 29439367 DOI: 10.3233/rnn-170780] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND Retinal ganglion cells (RGCs) of mammals lose the ability to regenerate injured axons during postnatal maturation, but little is known about the underlying molecular mechanisms. OBJECTIVE It remains of particular importance to understand the mechanisms of axonal regeneration to develop new therapeutic approaches for nerve injuries. METHODS Retinas from newborn to adult monkeys (Callithrix jacchus)1 were obtained immediately after death and cultured in vitro. Growths of axons were monitored using microscopy and time-lapse video cinematography. Immunohistochemistry, Western blotting, qRT-PCR, and genomics were performed to characterize molecules associated with axonal regeneration and growth. A genomic screen was performed by using retinal explants versus native and non-regenerative explants obtained from eye cadavers on the day of birth, and hybridizing the mRNA with cross-reacting cDNA on conventional human microarrays. Followed the genomic screen, siRNA experiments were conducted to identify the functional involvement of identified candidates. RESULTS Neuron-specific human ribonucleoprotein N (snRPN) was found to be a potential regulator of impaired axonal regeneration during neuronal maturation in these animals. In particular, up-regulation of snRPN was observed during retinal maturation, coinciding with a decline in regenerative ability. Axon regeneration was reactivated in snRPN-knockout retinal ex vivo explants of adult monkey. CONCLUSION These results suggest that coordinated snRPN-driven activities within the neuron-specific ribonucleoprotein complex regulate the regenerative ability of RGCs in primates, thereby highlighting a potential new role for snRPN within neurons and the possibility of novel postinjury therapies.
Collapse
Affiliation(s)
- Sonja Mertsch
- Institute of Experimental Ophthalmology and DFG-Excellence Center, Cells in Motion (CiM, area C.4), School of Medicine, University of Münster, Münster, Germany.,Department of Ophthalmology, Laboratory of Experimental Ophthalmology, University Clinic Duesseldorf, Duesseldorf, Germany
| | - Katrin Schlicht
- Institute of Experimental Ophthalmology and DFG-Excellence Center, Cells in Motion (CiM, area C.4), School of Medicine, University of Münster, Münster, Germany
| | - Harutyun Melkonyan
- Institute of Experimental Ophthalmology and DFG-Excellence Center, Cells in Motion (CiM, area C.4), School of Medicine, University of Münster, Münster, Germany
| | - Stefan Schlatt
- Institute of Regenerative Medicine (CeRA) and DFG-Excellence Center, Cells in Motion (CiM, area A.2), School of Medicine, University of Münster, Münster, Germany
| | - Solon Thanos
- Institute of Experimental Ophthalmology and DFG-Excellence Center, Cells in Motion (CiM, area C.4), School of Medicine, University of Münster, Münster, Germany
| |
Collapse
|
18
|
Bowerman M, Becker CG, Yáñez-Muñoz RJ, Ning K, Wood MJA, Gillingwater TH, Talbot K. Therapeutic strategies for spinal muscular atrophy: SMN and beyond. Dis Model Mech 2018; 10:943-954. [PMID: 28768735 PMCID: PMC5560066 DOI: 10.1242/dmm.030148] [Citation(s) in RCA: 64] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Spinal muscular atrophy (SMA) is a devastating neuromuscular disorder characterized by loss of motor neurons and muscle atrophy, generally presenting in childhood. SMA is caused by low levels of the survival motor neuron protein (SMN) due to inactivating mutations in the encoding gene SMN1. A second duplicated gene, SMN2, produces very little but sufficient functional protein for survival. Therapeutic strategies to increase SMN are in clinical trials, and the first SMN2-directed antisense oligonucleotide (ASO) therapy has recently been licensed. However, several factors suggest that complementary strategies may be needed for the long-term maintenance of neuromuscular and other functions in SMA patients. Pre-clinical SMA models demonstrate that the requirement for SMN protein is highest when the structural connections of the neuromuscular system are being established, from late fetal life throughout infancy. Augmenting SMN may not address the slow neurodegenerative process underlying progressive functional decline beyond childhood in less severe types of SMA. Furthermore, individuals receiving SMN-based treatments may be vulnerable to delayed symptoms if rescue of the neuromuscular system is incomplete. Finally, a large number of older patients living with SMA do not fulfill the present criteria for inclusion in gene therapy and ASO clinical trials, and may not benefit from SMN-inducing treatments. Therefore, a comprehensive whole-lifespan approach to SMA therapy is required that includes both SMN-dependent and SMN-independent strategies that treat the CNS and periphery. Here, we review the range of non-SMN pathways implicated in SMA pathophysiology and discuss how various model systems can serve as valuable tools for SMA drug discovery. Summary: Translational research for spinal muscular atrophy (SMA) should address the development of non-CNS and survival motor neuron (SMN)-independent therapeutic approaches to complement and enhance the benefits of CNS-directed and SMN-dependent therapies.
Collapse
Affiliation(s)
- Melissa Bowerman
- Department of Physiology, Anatomy and Genetics, University of Oxford, South Parks Road, Oxford OX1 3QX, UK
| | - Catherina G Becker
- Euan MacDonald Centre for Motor Neurone Disease Research and Centre for Neuroregeneration, University of Edinburgh, Edinburgh EH16 4SB, UK
| | - Rafael J Yáñez-Muñoz
- AGCTlab.org, Centre for Biomedical Sciences, School of Biological Sciences, Royal Holloway, University of London, Egham Hill, Egham, Surrey TW20 0EX, UK
| | - Ke Ning
- Department of Neuroscience, Sheffield Institute for Translational Neuroscience (SITraN), University of Sheffield, Sheffield S10 2HQ, UK
| | - Matthew J A Wood
- Department of Physiology, Anatomy and Genetics, University of Oxford, South Parks Road, Oxford OX1 3QX, UK
| | - Thomas H Gillingwater
- Euan MacDonald Centre for Motor Neurone Disease Research and Centre for Integrative Physiology, University of Edinburgh, Edinburgh EH8 9XD, UK
| | - Kevin Talbot
- Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DU, UK
| | | |
Collapse
|
19
|
Abstract
Gemin3, also known as DDX20 or DP103, is a DEAD-box RNA helicase which is involved in more than one cellular process. Though RNA unwinding has been determined in vitro, it is surprisingly not required for all of its activities in cellular metabolism. Gemin3 is an essential gene, present in Amoeba and Metazoa. The highly conserved N-terminus hosts the helicase core, formed of the helicase- and DEAD-domains, which, based on crystal structure determination, have key roles in RNA binding. The C-terminus of Gemin3 is highly divergent between species and serves as the interaction site for several accessory factors that could recruit Gemin3 to its target substrates and/or modulate its function. This review article focuses on the known roles of Gemin3, first as a core member of the survival motor neuron (SMN) complex, in small nuclear ribonucleoprotein biogenesis. Although mechanistic details are lacking, a critical function for Gemin3 in this pathway is supported by numerous in vitro and in vivo studies. Gene expression activities of Gemin3 are next underscored, mainly messenger ribonucleoprotein trafficking, gene silencing via microRNA processing, and transcriptional regulation. The involvement of Gemin3 in abnormal cell signal transduction pathways involving p53 and NF-κB is also highlighted. Finally, the clinical implications of Gemin3 deregulation are discussed including links to spinal muscular atrophy, poliomyelitis, amyotrophic lateral sclerosis, and cancer. Impressive progress made over the past two decades since the discovery of Gemin3 bodes well for further work that refines the mechanism(s) underpinning its multiple activities.
Collapse
|
20
|
Meier ID, Walker MP, Matera AG. Gemin4 is an essential gene in mice, and its overexpression in human cells causes relocalization of the SMN complex to the nucleoplasm. Biol Open 2018; 7:bio.032409. [PMID: 29371219 PMCID: PMC5861365 DOI: 10.1242/bio.032409] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Gemin4 is a member of the Survival Motor Neuron (SMN) protein complex, which is responsible for the assembly and maturation of Sm-class small nuclear ribonucleoproteins (snRNPs). In metazoa, Sm snRNPs are assembled in the cytoplasm and subsequently imported into the nucleus. We previously showed that the SMN complex is required for snRNP import in vitro, although it remains unclear which specific components direct this process. Here, we report that Gemin4 overexpression drives SMN and the other Gemin proteins from the cytoplasm into the nucleus. Moreover, it disrupts the subnuclear localization of the Cajal body marker protein, coilin, in a dose-dependent manner. We identified three putative nuclear localization signal (NLS) motifs within Gemin4, one of which is necessary and sufficient to direct nuclear import. Overexpression of Gemin4 constructs lacking this NLS sequestered Gemin3 and, to a lesser extent Gemin2, in the cytoplasm but had little effect on the nuclear accumulation of SMN. We also investigated the effects of Gemin4 depletion in the laboratory mouse, Mus musculus. Gemin4 null mice die early in embryonic development, demonstrating that Gemin4 is an essential mammalian protein. When crossed onto a severe SMA mutant background, heterozygous loss of Gemin4 failed to modify the early postnatal mortality phenotype of SMA type I (Smn−/−;SMN2+/+) mice. We conclude that Gemin4 plays an essential role in mammalian snRNP biogenesis, and may facilitate import of the SMN complex (or subunits thereof) into the nucleus. Summary:Gemin4 loss-of-function is recessive lethal in mice, whereas in cell culture its overexpression results in a dominant, gain-of-function relocalization of SMN and other Gemin proteins to the nucleus.
Collapse
Affiliation(s)
- Ingo D Meier
- Integrative Program for Biological and Genome Sciences, Departments of Biology and Genetics, Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC 27599-3280, USA
| | - Michael P Walker
- Integrative Program for Biological and Genome Sciences, Departments of Biology and Genetics, Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC 27599-3280, USA.,Department of Genetics, Case Western Reserve University, Cleveland, OH 44106-4955, USA
| | | |
Collapse
|
21
|
Piras A, Schiaffino L, Boido M, Valsecchi V, Guglielmotto M, De Amicis E, Puyal J, Garcera A, Tamagno E, Soler RM, Vercelli A. Inhibition of autophagy delays motoneuron degeneration and extends lifespan in a mouse model of spinal muscular atrophy. Cell Death Dis 2017; 8:3223. [PMID: 29259166 PMCID: PMC5870600 DOI: 10.1038/s41419-017-0086-4] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2017] [Revised: 09/12/2017] [Accepted: 10/05/2017] [Indexed: 12/26/2022]
Abstract
Spinal muscular atrophy (SMA) is a recessive autosomal neuromuscular disease, due to homozygous mutations or deletions in the telomeric survival motoneuron gene 1 (SMN1). SMA is characterized by motor impairment, muscle atrophy, and premature death following motor neuron (MN) degeneration. Emerging evidence suggests that dysregulation of autophagy contributes to MN degeneration. We here investigated the role of autophagy in the SMNdelta7 mouse model of SMA II (intermediate form of the disease) which leads to motor impairment by postnatal day 5 (P5) and to death by P13. We first showed by immunoblots that Beclin 1 and LC3-II expression levels increased in the lumbar spinal cord of the SMA pups. Electron microscopy and immunofluorescence studies confirmed that autophagic markers were enhanced in the ventral horn of SMA pups. To clarify the role of autophagy, we administered intracerebroventricularly (at P3) either an autophagy inhibitor (3-methyladenine, 3-MA), or an autophagy inducer (rapamycin) in SMA pups. Motor behavior was assessed daily with different tests: tail suspension, righting reflex, and hindlimb suspension tests. 3-MA significantly improved motor performance, extended the lifespan, and delayed MN death in lumbar spinal cord (10372.36 ± 2716 MNs) compared to control-group (5148.38 ± 94 MNs). Inhibition of autophagy by 3-MA suppressed autophagosome formation, reduced the apoptotic activation (cleaved caspase-3 and Bcl2) and the appearance of terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL)-positive neurons, underlining that apoptosis and autophagy pathways are intricately intertwined. Therefore, autophagy is likely involved in MN death in SMA II, suggesting that it might represent a promising target for delaying the progression of SMA in humans as well.
Collapse
Affiliation(s)
- Antonio Piras
- Department of Neuroscience, University of Torino, Torino, Italy. .,Neuroscience Institute Cavalieri Ottolenghi (NICO), University of Torino, Torino, Italy. .,Karolinska Institutet, Dept NVS, Center for Alzheimer Research, Division for Neurogeriatrics, 141 57, Huddinge, Sweden.
| | - Lorenzo Schiaffino
- Department of Neuroscience, University of Torino, Torino, Italy.,Neuroscience Institute Cavalieri Ottolenghi (NICO), University of Torino, Torino, Italy
| | - Marina Boido
- Department of Neuroscience, University of Torino, Torino, Italy.,Neuroscience Institute Cavalieri Ottolenghi (NICO), University of Torino, Torino, Italy
| | - Valeria Valsecchi
- Department of Neuroscience, University of Torino, Torino, Italy.,Neuroscience Institute Cavalieri Ottolenghi (NICO), University of Torino, Torino, Italy
| | - Michela Guglielmotto
- Department of Neuroscience, University of Torino, Torino, Italy.,Neuroscience Institute Cavalieri Ottolenghi (NICO), University of Torino, Torino, Italy
| | - Elena De Amicis
- Department of Neuroscience, University of Torino, Torino, Italy.,Neuroscience Institute Cavalieri Ottolenghi (NICO), University of Torino, Torino, Italy
| | - Julien Puyal
- Department of Fundamental Neurosciences, University of Lausanne, Lausanne, Switzerland
| | - Ana Garcera
- Unitat de Senyalització Neuronal, Dep. Medicina Experimental, Universitat de Lleida-IRBLLEIDA, Rovira Roure 80, 25198, Lleida, Spain
| | - Elena Tamagno
- Department of Neuroscience, University of Torino, Torino, Italy.,Neuroscience Institute Cavalieri Ottolenghi (NICO), University of Torino, Torino, Italy
| | - Rosa M Soler
- Unitat de Senyalització Neuronal, Dep. Medicina Experimental, Universitat de Lleida-IRBLLEIDA, Rovira Roure 80, 25198, Lleida, Spain
| | - Alessandro Vercelli
- Department of Neuroscience, University of Torino, Torino, Italy.,Neuroscience Institute Cavalieri Ottolenghi (NICO), University of Torino, Torino, Italy
| |
Collapse
|
22
|
Lanfranco M, Cacciottolo R, Borg RM, Vassallo N, Juge F, Bordonné R, Cauchi RJ. Novel interactors of the Drosophila
Survival Motor Neuron (SMN) Complex suggest its full conservation. FEBS Lett 2017; 591:3600-3614. [DOI: 10.1002/1873-3468.12853] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Revised: 09/14/2017] [Accepted: 09/14/2017] [Indexed: 12/20/2022]
Affiliation(s)
- Maia Lanfranco
- Institut de Génétique Moléculaire de Montpellier; CNRS-UMR 5535; Université de Montpellier; France
- Department of Physiology and Biochemistry; Faculty of Medicine and Surgery; University of Malta; Msida Malta
- Centre for Molecular Medicine and Biobanking; University of Malta; Msida Malta
| | - Rebecca Cacciottolo
- Department of Physiology and Biochemistry; Faculty of Medicine and Surgery; University of Malta; Msida Malta
- Centre for Molecular Medicine and Biobanking; University of Malta; Msida Malta
| | - Rebecca M. Borg
- Institut de Génétique Moléculaire de Montpellier; CNRS-UMR 5535; Université de Montpellier; France
- Department of Physiology and Biochemistry; Faculty of Medicine and Surgery; University of Malta; Msida Malta
- Centre for Molecular Medicine and Biobanking; University of Malta; Msida Malta
| | - Neville Vassallo
- Department of Physiology and Biochemistry; Faculty of Medicine and Surgery; University of Malta; Msida Malta
- Centre for Molecular Medicine and Biobanking; University of Malta; Msida Malta
| | - François Juge
- Institut de Génétique Moléculaire de Montpellier; CNRS-UMR 5535; Université de Montpellier; France
| | - Rémy Bordonné
- Institut de Génétique Moléculaire de Montpellier; CNRS-UMR 5535; Université de Montpellier; France
| | - Ruben J. Cauchi
- Department of Physiology and Biochemistry; Faculty of Medicine and Surgery; University of Malta; Msida Malta
- Centre for Molecular Medicine and Biobanking; University of Malta; Msida Malta
| |
Collapse
|
23
|
Patel N, Anand D, Monies D, Maddirevula S, Khan AO, Algoufi T, Alowain M, Faqeih E, Alshammari M, Qudair A, Alsharif H, Aljubran F, Alsaif HS, Ibrahim N, Abdulwahab FM, Hashem M, Alsedairy H, Aldahmesh MA, Lachke SA, Alkuraya FS. Novel phenotypes and loci identified through clinical genomics approaches to pediatric cataract. Hum Genet 2016; 136:205-225. [PMID: 27878435 DOI: 10.1007/s00439-016-1747-6] [Citation(s) in RCA: 64] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2016] [Accepted: 11/16/2016] [Indexed: 01/17/2023]
Abstract
Pediatric cataract is highly heterogeneous clinically and etiologically. While mostly isolated, cataract can be part of many multisystem disorders, further complicating the diagnostic process. In this study, we applied genomic tools in the form of a multi-gene panel as well as whole-exome sequencing on unselected cohort of pediatric cataract (166 patients from 74 families). Mutations in previously reported cataract genes were identified in 58% for a total of 43 mutations, including 15 that are novel. GEMIN4 was independently mutated in families with a syndrome of cataract, global developmental delay with or without renal involvement. We also highlight a recognizable syndrome that resembles galactosemia (a fulminant infantile liver disease with cataract) caused by biallelic mutations in CYP51A1. A founder mutation in RIC1 (KIAA1432) was identified in patients with cataract, brain atrophy, microcephaly with or without cleft lip and palate. For non-syndromic pediatric cataract, we map a novel locus in a multiplex consanguineous family on 4p15.32 where exome sequencing revealed a homozygous truncating mutation in TAPT1. We report two further candidates that are biallelically inactivated each in a single cataract family: TAF1A (cataract with global developmental delay) and WDR87 (non-syndromic cataract). In addition to positional mapping data, we use iSyTE developmental lens expression and gene-network analysis to corroborate the proposed link between the novel candidate genes and cataract. Our study expands the phenotypic, allelic and locus heterogeneity of pediatric cataract. The high diagnostic yield of clinical genomics supports the adoption of this approach in this patient group.
Collapse
Affiliation(s)
- Nisha Patel
- Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - Deepti Anand
- Department of Biological Sciences, University of Delaware, Newark, DE, 19716, USA
| | - Dorota Monies
- Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia.,Saudi Human Genome Program, King Abdulaziz City for Science and Technology, Riyadh, Saudi Arabia
| | - Sateesh Maddirevula
- Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - Arif O Khan
- Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia.,Eye Institute, Cleveland Clinic Abu Dhabi, Abu Dhabi, United Arab Emirates
| | - Talal Algoufi
- Department of Pediatrics, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia
| | - Mohammed Alowain
- Department of Medical Genetics, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia
| | - Eissa Faqeih
- Department of Pediatrics, King Fahad Medical City, Riyadh, Saudi Arabia
| | - Muneera Alshammari
- Department of Pediatrics, King Khalid University Hospital and College of Medicine, King Saud University, Riyadh, Saudi Arabia
| | - Ahmed Qudair
- Department of Medical Genetics, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia
| | - Hadeel Alsharif
- Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - Fatimah Aljubran
- Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - Hessa S Alsaif
- Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - Niema Ibrahim
- Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - Firdous M Abdulwahab
- Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - Mais Hashem
- Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - Haifa Alsedairy
- Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - Mohammed A Aldahmesh
- Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - Salil A Lachke
- Department of Biological Sciences, University of Delaware, Newark, DE, 19716, USA.,Center for Bioinformatics and Computational Biology, University of Delaware, Newark, DE, 19716, USA
| | - Fowzan S Alkuraya
- Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia. .,Department of Anatomy and Cell Biology, College of Medicine, Alfaisal University, Riyadh, Saudi Arabia.
| |
Collapse
|
24
|
Jin W, Wang Y, Liu CP, Yang N, Jin M, Cong Y, Wang M, Xu RM. Structural basis for snRNA recognition by the double-WD40 repeat domain of Gemin5. Genes Dev 2016; 30:2391-2403. [PMID: 27881601 PMCID: PMC5131779 DOI: 10.1101/gad.291377.116] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2016] [Accepted: 10/17/2016] [Indexed: 12/21/2022]
Abstract
Assembly of the spliceosomal small nuclear ribonucleoparticle (snRNP) core requires the participation of the multisubunit SMN (survival of motor neuron) complex, which contains SMN and several Gemin proteins. The SMN and Gemin2 subunits directly bind Sm proteins, and Gemin5 is required for snRNP biogenesis and has been implicated in snRNA recognition. The RNA sequence required for snRNP assembly includes the Sm site and an adjacent 3' stem-loop, but a precise understanding of Gemin5's RNA-binding specificity is lacking. Here we show that the N-terminal half of Gemin5, which is composed of two juxtaposed seven-bladed WD40 repeat domains, recognizes the Sm site. The tandem WD40 repeat domains are rigidly held together to form a contiguous RNA-binding surface. RNA-contacting residues are located mostly on loops between β strands on the apical surface of the WD40 domains. Structural and biochemical analyses show that base-stacking interactions involving four aromatic residues and hydrogen bonding by a pair of arginines are crucial for specific recognition of the Sm sequence. We also show that an adenine immediately 5' to the Sm site is required for efficient binding and that Gemin5 can bind short RNA oligos in an alternative mode. Our results provide mechanistic understandings of Gemin5's snRNA-binding specificity as well as valuable insights into the molecular mechanism of RNA binding by WD40 repeat proteins in general.
Collapse
Affiliation(s)
- Wenxing Jin
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Yi Wang
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China.,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Chao-Pei Liu
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Na Yang
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China.,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Mingliang Jin
- University of Chinese Academy of Sciences, Beijing 100049, China.,National Center for Protein Science Shanghai, State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 201210, China
| | - Yao Cong
- National Center for Protein Science Shanghai, State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 201210, China
| | - Mingzhu Wang
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Rui-Ming Xu
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China.,University of Chinese Academy of Sciences, Beijing 100049, China
| |
Collapse
|
25
|
Colicino E, Giuliano G, Power MC, Lepeule J, Wilker EH, Vokonas P, Brennan KJM, Fossati S, Hoxha M, Spiro A, Weisskopf MG, Schwartz J, Baccarelli AA. Long-term exposure to black carbon, cognition and single nucleotide polymorphisms in microRNA processing genes in older men. ENVIRONMENT INTERNATIONAL 2016; 88:86-93. [PMID: 26724585 PMCID: PMC4755894 DOI: 10.1016/j.envint.2015.12.014] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2015] [Revised: 12/02/2015] [Accepted: 12/13/2015] [Indexed: 05/04/2023]
Abstract
INTRODUCTION Air pollution exposure has been linked to impaired cognitive aging, but little is known about biomarkers modifying this association. MicroRNAs (miRNAs) control gene expression and neuronal programming. miRNA levels vary due to single nucleotide polymorphisms (SNPs) in genes processing miRNAs from precursor molecules. OBJECTIVES To investigate whether SNPs in miRNA-processing genes are associated with cognition and modify the relationship between black carbon (BC), marker of traffic-related pollution, and cognitive functions. METHODS 533 Normative Aging Study men (mean±SD 72±7years) were tested ≤4 times (mean=1.7 times) using seven cognitive tests between 1995 and 2007. We tested interactions of 16 miRNA-related SNPs with 1-year average BC from a validated land-use-regression model. We used covariate-adjusted logistic regression for low (≤25) Mini-Mental tate Examination (MMSE) and mixed-effect regression for a global cognitive score combining six other tests. RESULTS Global cognition was negatively associated with the homozygous minor variant of rs595961 AGO1 (-0.42SD; 95%CI: (-0.71, -0.13)) relative to the major variant. BC-MMSE association was stronger in heterozygous carriers of rs11077 XPO5 (OR=1.99; 95%CI: (1.39, 2.85)) and minor variant carriers of GEMIN4 rs2740348 (OR=1.34; 95%CI: (1.05, 1.7)), compared to their major variant. The BC-global-cognition association was stronger in heterozygous carriers of GEMIN4 rs4968104 (-0.10SD; 95%CI: (-0.18, -0.02)), and GEMIN4 rs910924 (-0.09SD; 95%CI: (-0.17, -0.02)) relative to the major variant. Blood miRNA expression analyses showed associations only of XPO5 rs11077 with miR-9 and miR-96. CONCLUSIONS Carriers of particular miRNA-processing SNPs had higher susceptibility to BC in BC-cognition associations, possibly due to influences on miRNA expression.
Collapse
Affiliation(s)
- Elena Colicino
- Department of Environmental Health, Harvard T.H. Chan School of Public Health, 677 Huntington Avenue, Boston, MA 02115, USA.
| | - Giulia Giuliano
- Department of Environmental Health, Harvard T.H. Chan School of Public Health, 677 Huntington Avenue, Boston, MA 02115, USA.
| | - Melinda C Power
- Department of Environmental Health, Harvard T.H. Chan School of Public Health, 677 Huntington Avenue, Boston, MA 02115, USA; Department of Epidemiology, Harvard T.H. Chan School of Public Health, 677 Huntington Avenue, Boston, MA 02115, USA.
| | - Johanna Lepeule
- Department of Environmental Health, Harvard T.H. Chan School of Public Health, 677 Huntington Avenue, Boston, MA 02115, USA.
| | - Elissa H Wilker
- Department of Environmental Health, Harvard T.H. Chan School of Public Health, 677 Huntington Avenue, Boston, MA 02115, USA; Cardiovascular Epidemiology Research Unit, Beth Israel Deaconess Medical Center, 330 Brookline Avenue, Boston, MA 02215, USA.
| | - Pantel Vokonas
- VA Boston Healthcare System and Boston University Schools of Public Health and Medicine, 330 Brookline Avenue, Boston, MA 02215, USA.
| | - Kasey J M Brennan
- Department of Environmental Health, Harvard T.H. Chan School of Public Health, 677 Huntington Avenue, Boston, MA 02115, USA.
| | - Serena Fossati
- Department of Environmental Health, Harvard T.H. Chan School of Public Health, 677 Huntington Avenue, Boston, MA 02115, USA; Department of Biomedical and Clinical Sciences "L. Sacco", University of Milan, Via Festa del Perdono, 7, 20122 Milano, Italy.
| | - Mirjam Hoxha
- Department of Clinical Sciences and Community Health, University of Milan, Via Festa del Perdono, 7, 20122 Milano, Italy; Epidemiology Unit, Department of Preventive Medicine, Foundation IRCCS Cà Granda Ospedale Maggiore Policlinico, Via Francesco Sforza, 33, 20122 Milano, Italy.
| | - Avron Spiro
- VA Boston Healthcare System and Boston University Schools of Public Health and Medicine, 330 Brookline Avenue, Boston, MA 02215, USA.
| | - Marc G Weisskopf
- Department of Environmental Health, Harvard T.H. Chan School of Public Health, 677 Huntington Avenue, Boston, MA 02115, USA; Department of Epidemiology, Harvard T.H. Chan School of Public Health, 677 Huntington Avenue, Boston, MA 02115, USA.
| | - Joel Schwartz
- Department of Environmental Health, Harvard T.H. Chan School of Public Health, 677 Huntington Avenue, Boston, MA 02115, USA; Department of Epidemiology, Harvard T.H. Chan School of Public Health, 677 Huntington Avenue, Boston, MA 02115, USA.
| | - Andrea A Baccarelli
- Department of Environmental Health, Harvard T.H. Chan School of Public Health, 677 Huntington Avenue, Boston, MA 02115, USA; Department of Epidemiology, Harvard T.H. Chan School of Public Health, 677 Huntington Avenue, Boston, MA 02115, USA.
| |
Collapse
|
26
|
Tang AY. RNA processing-associated molecular mechanisms of neurodegenerative diseases. J Appl Genet 2015; 57:323-33. [DOI: 10.1007/s13353-015-0330-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2015] [Revised: 11/22/2015] [Accepted: 11/26/2015] [Indexed: 12/13/2022]
|
27
|
Bizarro J, Dodré M, Huttin A, Charpentier B, Schlotter F, Branlant C, Verheggen C, Massenet S, Bertrand E. NUFIP and the HSP90/R2TP chaperone bind the SMN complex and facilitate assembly of U4-specific proteins. Nucleic Acids Res 2015; 43:8973-89. [PMID: 26275778 PMCID: PMC4605303 DOI: 10.1093/nar/gkv809] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2015] [Accepted: 07/27/2015] [Indexed: 12/17/2022] Open
Abstract
The Sm proteins are loaded on snRNAs by the SMN complex, but how snRNP-specific proteins are assembled remains poorly characterized. U4 snRNP and box C/D snoRNPs have structural similarities. They both contain the 15.5K and proteins with NOP domains (PRP31 for U4, NOP56/58 for snoRNPs). Biogenesis of box C/D snoRNPs involves NUFIP and the HSP90/R2TP chaperone system and here, we explore the function of this machinery in U4 RNP assembly. We show that yeast Prp31 interacts with several components of the NUFIP/R2TP machinery, and that these interactions are separable from each other. In human cells, PRP31 mutants that fail to stably associate with U4 snRNA still interact with components of the NUFIP/R2TP system, indicating that these interactions precede binding of PRP31 to U4 snRNA. Knock-down of NUFIP leads to mislocalization of PRP31 and decreased association with U4. Moreover, NUFIP is associated with the SMN complex through direct interactions with Gemin3 and Gemin6. Altogether, our data suggest a model in which the NUFIP/R2TP system is connected with the SMN complex and facilitates assembly of U4 snRNP-specific proteins.
Collapse
Affiliation(s)
- Jonathan Bizarro
- Equipe labélisée Ligue contre le Cancer, Institut de Génétique Moléculaire de Montpellier, IGMM-UMR 5535 du CNRS-Université de Montpellier, 1919, route de Mende, 34293 Montpellier Cedex 5, France
| | - Maxime Dodré
- Ingénierie Moléculaire et Physiopathologie Articulaire, UMR 7365 CNRS-Université de Lorraine, Biopôle de l'Université de Lorraine, avenue de la forêt de Haye, BP 184, 54505 Vandoeuvre-les-Nancy Cedex, France
| | - Alexandra Huttin
- Ingénierie Moléculaire et Physiopathologie Articulaire, UMR 7365 CNRS-Université de Lorraine, Biopôle de l'Université de Lorraine, avenue de la forêt de Haye, BP 184, 54505 Vandoeuvre-les-Nancy Cedex, France
| | - Bruno Charpentier
- Ingénierie Moléculaire et Physiopathologie Articulaire, UMR 7365 CNRS-Université de Lorraine, Biopôle de l'Université de Lorraine, avenue de la forêt de Haye, BP 184, 54505 Vandoeuvre-les-Nancy Cedex, France
| | - Florence Schlotter
- Ingénierie Moléculaire et Physiopathologie Articulaire, UMR 7365 CNRS-Université de Lorraine, Biopôle de l'Université de Lorraine, avenue de la forêt de Haye, BP 184, 54505 Vandoeuvre-les-Nancy Cedex, France
| | - Christiane Branlant
- Ingénierie Moléculaire et Physiopathologie Articulaire, UMR 7365 CNRS-Université de Lorraine, Biopôle de l'Université de Lorraine, avenue de la forêt de Haye, BP 184, 54505 Vandoeuvre-les-Nancy Cedex, France
| | - Céline Verheggen
- Equipe labélisée Ligue contre le Cancer, Institut de Génétique Moléculaire de Montpellier, IGMM-UMR 5535 du CNRS-Université de Montpellier, 1919, route de Mende, 34293 Montpellier Cedex 5, France
| | - Séverine Massenet
- Ingénierie Moléculaire et Physiopathologie Articulaire, UMR 7365 CNRS-Université de Lorraine, Biopôle de l'Université de Lorraine, avenue de la forêt de Haye, BP 184, 54505 Vandoeuvre-les-Nancy Cedex, France
| | - Edouard Bertrand
- Equipe labélisée Ligue contre le Cancer, Institut de Génétique Moléculaire de Montpellier, IGMM-UMR 5535 du CNRS-Université de Montpellier, 1919, route de Mende, 34293 Montpellier Cedex 5, France
| |
Collapse
|
28
|
Neuenkirchen N, Englbrecht C, Ohmer J, Ziegenhals T, Chari A, Fischer U. Reconstitution of the human U snRNP assembly machinery reveals stepwise Sm protein organization. EMBO J 2015; 34:1925-41. [PMID: 26069323 DOI: 10.15252/embj.201490350] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2014] [Accepted: 05/12/2015] [Indexed: 11/09/2022] Open
Abstract
The assembly of spliceosomal U snRNPs depends on the coordinated action of PRMT5 and SMN complexes in vivo. These trans-acting factors enable the faithful delivery of seven Sm proteins onto snRNA and the formation of the common core of snRNPs. To gain mechanistic insight into their mode of action, we reconstituted the assembly machinery from recombinant sources. We uncover a stepwise and ordered formation of distinct Sm protein complexes on the PRMT5 complex, which is facilitated by the assembly chaperone pICln. Upon completion, the formed pICln-Sm units are displaced by new pICln-Sm protein substrates and transferred onto the SMN complex. The latter acts as a Brownian machine that couples spontaneous conformational changes driven by thermal energy to prevent mis-assembly and to ensure the transfer of Sm proteins to cognate RNA. Investigation of mutant SMN complexes provided insight into the contribution of individual proteins to these activities. The biochemical reconstitution presented here provides a basis for a detailed molecular dissection of the U snRNP assembly reaction.
Collapse
Affiliation(s)
- Nils Neuenkirchen
- Department of Biochemistry, Biocenter, University of Würzburg, Würzburg, Germany
| | - Clemens Englbrecht
- Department of Biochemistry, Biocenter, University of Würzburg, Würzburg, Germany
| | - Jürgen Ohmer
- Department of Biochemistry, Biocenter, University of Würzburg, Würzburg, Germany
| | - Thomas Ziegenhals
- Department of Biochemistry, Biocenter, University of Würzburg, Würzburg, Germany
| | - Ashwin Chari
- Research Group of 3D Electron Cryomicroscopy, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Utz Fischer
- Department of Biochemistry, Biocenter, University of Würzburg, Würzburg, Germany Department of Radiation Medicine and Applied Sciences, University of California, San Diego, San Diego, CA, USA
| |
Collapse
|
29
|
Valsecchi V, Boido M, De Amicis E, Piras A, Vercelli A. Expression of Muscle-Specific MiRNA 206 in the Progression of Disease in a Murine SMA Model. PLoS One 2015; 10:e0128560. [PMID: 26030275 PMCID: PMC4450876 DOI: 10.1371/journal.pone.0128560] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Accepted: 04/28/2015] [Indexed: 12/13/2022] Open
Abstract
Spinal muscular atrophy (SMA) is a severe neuromuscular disease, the most common in infancy, and the third one among young people under 18 years. The major pathological landmark of SMA is a selective degeneration of lower motor neurons, resulting in progressive skeletal muscle denervation, atrophy, and paralysis. Recently, it has been shown that specific or general changes in the activity of ribonucleoprotein containing micro RNAs (miRNAs) play a role in the development of SMA. Additionally miRNA-206 has been shown to be required for efficient regeneration of neuromuscular synapses after acute nerve injury in an ALS mouse model. Therefore, we correlated the morphology and the architecture of the neuromuscular junctions (NMJs) of quadriceps, a muscle affected in the early stage of the disease, with the expression levels of miRNA-206 in a mouse model of intermediate SMA (SMAII), one of the most frequently used experimental model. Our results showed a decrease in the percentage of type II fibers, an increase in atrophic muscle fibers and a remarkable accumulation of neurofilament (NF) in the pre-synaptic terminal of the NMJs in the quadriceps of SMAII mice. Furthermore, molecular investigation showed a direct link between miRNA-206-HDAC4-FGFBP1, and in particular, a strong up-regulation of this pathway in the late phase of the disease. We propose that miRNA-206 is activated as survival endogenous mechanism, although not sufficient to rescue the integrity of motor neurons. We speculate that early modulation of miRNA-206 expression might delay SMA neurodegenerative pathway and that miRNA-206 could be an innovative, still relatively unexplored, therapeutic target for SMA.
Collapse
Affiliation(s)
- Valeria Valsecchi
- Neuroscience Institute Cavalieri Ottolenghi, Department of Neuroscience, University of Turin, Turin, Italy
| | - Marina Boido
- Neuroscience Institute Cavalieri Ottolenghi, Department of Neuroscience, University of Turin, Turin, Italy
| | - Elena De Amicis
- Neuroscience Institute Cavalieri Ottolenghi, Department of Neuroscience, University of Turin, Turin, Italy
| | - Antonio Piras
- Neuroscience Institute Cavalieri Ottolenghi, Department of Neuroscience, University of Turin, Turin, Italy
| | - Alessandro Vercelli
- Neuroscience Institute Cavalieri Ottolenghi, Department of Neuroscience, University of Turin, Turin, Italy
| |
Collapse
|
30
|
Yang J, Fuller PJ, Morgan J, Shibata H, Clyne CD, Young MJ. GEMIN4 functions as a coregulator of the mineralocorticoid receptor. J Mol Endocrinol 2015; 54:149-60. [PMID: 25555524 DOI: 10.1530/jme-14-0078] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
The mineralocorticoid receptor (MR) is a member of the nuclear receptor superfamily. Pathological activation of the MR causes cardiac fibrosis and heart failure, but clinical use of MR antagonists is limited by the renal side effect of hyperkalemia. Coregulator proteins are known to be critical for nuclear receptor-mediated gene expression. Identification of coregulators, which mediate MR activity in a tissue-specific manner, may allow for the development of novel tissue-selective MR modulators that confer cardiac protection without adverse renal effects. Our earlier studies identified a consensus motif among MR-interacting peptides, MPxLxxLL. Gem (nuclear organelle)-associated protein 4 (GEMIN4) is one of the proteins that contain this motif. Transient transfection experiments in HEK293 and H9c2 cells demonstrated that GEMIN4 repressed agonist-induced MR transactivation in a cell-specific manner. Furthermore, overexpression of GEMIN4 significantly decreased, while knockdown of GEMIN4 increased, the mRNA expression of specific endogenous MR target genes. A physical interaction between GEMIN4 and MR is suggested by their nuclear co-localization upon agonist treatment. These findings indicate that GEMIN4 functions as a novel coregulator of the MR.
Collapse
Affiliation(s)
- Jun Yang
- MIMR-PHI InstitutePO Box 5152, Clayton, Victoria 3168, AustraliaDepartment of MedicineMonash University, Clayton, Victoria 3168, AustraliaDepartment of EndocrinologyMetabolism, Rheumatology and Nephrology, Oita University, Yufu 879-5593, Japan MIMR-PHI InstitutePO Box 5152, Clayton, Victoria 3168, AustraliaDepartment of MedicineMonash University, Clayton, Victoria 3168, AustraliaDepartment of EndocrinologyMetabolism, Rheumatology and Nephrology, Oita University, Yufu 879-5593, Japan
| | - Peter J Fuller
- MIMR-PHI InstitutePO Box 5152, Clayton, Victoria 3168, AustraliaDepartment of MedicineMonash University, Clayton, Victoria 3168, AustraliaDepartment of EndocrinologyMetabolism, Rheumatology and Nephrology, Oita University, Yufu 879-5593, Japan MIMR-PHI InstitutePO Box 5152, Clayton, Victoria 3168, AustraliaDepartment of MedicineMonash University, Clayton, Victoria 3168, AustraliaDepartment of EndocrinologyMetabolism, Rheumatology and Nephrology, Oita University, Yufu 879-5593, Japan
| | - James Morgan
- MIMR-PHI InstitutePO Box 5152, Clayton, Victoria 3168, AustraliaDepartment of MedicineMonash University, Clayton, Victoria 3168, AustraliaDepartment of EndocrinologyMetabolism, Rheumatology and Nephrology, Oita University, Yufu 879-5593, Japan
| | - Hirotaka Shibata
- MIMR-PHI InstitutePO Box 5152, Clayton, Victoria 3168, AustraliaDepartment of MedicineMonash University, Clayton, Victoria 3168, AustraliaDepartment of EndocrinologyMetabolism, Rheumatology and Nephrology, Oita University, Yufu 879-5593, Japan
| | - Colin D Clyne
- MIMR-PHI InstitutePO Box 5152, Clayton, Victoria 3168, AustraliaDepartment of MedicineMonash University, Clayton, Victoria 3168, AustraliaDepartment of EndocrinologyMetabolism, Rheumatology and Nephrology, Oita University, Yufu 879-5593, Japan
| | - Morag J Young
- MIMR-PHI InstitutePO Box 5152, Clayton, Victoria 3168, AustraliaDepartment of MedicineMonash University, Clayton, Victoria 3168, AustraliaDepartment of EndocrinologyMetabolism, Rheumatology and Nephrology, Oita University, Yufu 879-5593, Japan MIMR-PHI InstitutePO Box 5152, Clayton, Victoria 3168, AustraliaDepartment of MedicineMonash University, Clayton, Victoria 3168, AustraliaDepartment of EndocrinologyMetabolism, Rheumatology and Nephrology, Oita University, Yufu 879-5593, Japan
| |
Collapse
|
31
|
Chen YC, Chang JG, Jong YJ, Liu TY, Yuo CY. High expression level of Tra2-β1 is responsible for increased SMN2 exon 7 inclusion in the testis of SMA mice. PLoS One 2015; 10:e0120721. [PMID: 25781985 PMCID: PMC4363149 DOI: 10.1371/journal.pone.0120721] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2014] [Accepted: 01/26/2015] [Indexed: 01/06/2023] Open
Abstract
Spinal muscular atrophy (SMA) is an inherited neuromuscular disease caused by deletion or mutation of SMN1 gene. All SMA patients carry a nearly identical SMN2 gene, which produces low level of SMN protein due to mRNA exon 7 exclusion. Previously, we found that the testis of SMA mice (smn−/− SMN2) expresses high level of SMN2 full-length mRNA, indicating a testis-specific mechanism for SMN2 exon 7 inclusion. To elucidate the underlying mechanism, we established primary cultures of testis cells from SMA mice and analyzed them for SMN2 exon 7 splicing. We found that primary testis cells after a 2-hour culture still expressed high level of SMN2 full-length mRNA, but the level decreased after longer cultures. We then compared the protein levels of relevant splicing factors, and found that the level of Tra2-β1 also decreased during testis cell culture, correlated with SMN2 full-length mRNA downregulation. In addition, the testis of SMA mice expressed the highest level of Tra2-β1 among the many tissues examined. Furthermore, overexpression of Tra2-β1, but not ASF/SF2, increased SMN2 minigene exon 7 inclusion in primary testis cells and spinal cord neurons, whereas knockdown of Tra2-β1 decreased SMN2 exon 7 inclusion in primary testis cells of SMA mice. Therefore, our results indicate that high expression level of Tra2-β1 is responsible for increased SMN2 exon 7 inclusion in the testis of SMA mice. This study also suggests that the expression level of Tra2-β1 may be a modifying factor of SMA disease and a potential target for SMA treatment.
Collapse
Affiliation(s)
- Yu-Chia Chen
- Graduate Institute of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Jan-Gowth Chang
- Epigenome Research Center, China Medical University Hospital, Taichung, Taiwan
- Department of Laboratory Medicine, China Medical University Hospital, Taichung, Taiwan
- School of Medicine, China Medical University, Taichung, Taiwan
| | - Yuh-Jyh Jong
- Graduate Institute of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
- Departments of Pediatrics and Clinical Laboratory, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan
- Department of Biological Science and Technology, National Chiao Tung University, Hsinchu, Taiwan
| | - Ting-Yuan Liu
- Graduate Institute of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Chung-Yee Yuo
- Department of Biomedical Science and Environmental Biology, Kaohsiung Medical University, Kaohsiung, Taiwan
- * E-mail:
| |
Collapse
|
32
|
Rafałowska J, Sulejczak D, Chrapusta SJ, Gadamski R, Dziewulska D. Diverse expression of selected SMN complex proteins in humans with sporadic amyotrophic lateral sclerosis and in a transgenic rat model of familial form of the disease. PLoS One 2014; 9:e104614. [PMID: 25122454 PMCID: PMC4133261 DOI: 10.1371/journal.pone.0104614] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2014] [Accepted: 07/15/2014] [Indexed: 11/18/2022] Open
Abstract
Background and Objective There is circumstantial evidence linking sporadic amyotrophic lateral sclerosis (ALS) cases to a malfunction or deficit of a multimeric SMN complex that scrutinizes cellular RNAs; the core of this complex is survival motor neuron (SMN, or gemin 1) protein. We intended to verify this hypothesis by comparing the expression of both SMN and several other functionally associated gemins in the anterior horn motoneurons of patients who died of sporadic ALS (sALS), of transgenic rats with overexpression of the mutated human superoxide dismutase 1 gene (SOD1G93A) that represent a model of familial ALS (fALS), and of the respective controls. Methods Using archival material of paraffin blocks with samples of human and rat spinal cords, immunohistochemical reactions with antibodies against SMN and gemins 2, 3, and 4 were performed and assessed by light microscopy. Results The expression of SMN and all other studied gemins was observed in motoneurons of sALS patients, fALS rats, and in all controls, although the intensity varied. The immunolabeling was most intense in sALS patients with relatively fast disease course, and decreased with increasing disease duration in both the human sALS and rat fALS material. Irrespective of the disease stage, sALS material showed no or very low gemin 2 immunoreactivity, while clear gemin 2 immnoreactivity was observed in all fALS rats and control material. Conclusion The deficient expression of gemin 2 in spinal cord motoneurons in human sALS may lead to a dysfunction and loss of neuroprotective action of the SMN complex.
Collapse
Affiliation(s)
- Janina Rafałowska
- Department of Experimental and Clinical Neuropathology, Mossakowski Medical Research Centre, Polish Academy of Sciences, Warsaw, Poland
| | - Dorota Sulejczak
- Department of Experimental Pharmacology, Mossakowski Medical Research Centre, Polish Academy of Sciences, Warsaw, Poland
| | - Stanisław J Chrapusta
- Department of Experimental Pharmacology, Mossakowski Medical Research Centre, Polish Academy of Sciences, Warsaw, Poland
| | - Roman Gadamski
- Department of Experimental and Clinical Neuropathology, Mossakowski Medical Research Centre, Polish Academy of Sciences, Warsaw, Poland
| | - Dorota Dziewulska
- Department of Experimental and Clinical Neuropathology, Mossakowski Medical Research Centre, Polish Academy of Sciences, Warsaw, Poland; Department of Neurology, Medical University of Warsaw, Warsaw, Poland
| |
Collapse
|
33
|
Kye MJ, Niederst ED, Wertz MH, Gonçalves IDCG, Akten B, Dover KZ, Peters M, Riessland M, Neveu P, Wirth B, Kosik KS, Sardi SP, Monani UR, Passini MA, Sahin M. SMN regulates axonal local translation via miR-183/mTOR pathway. Hum Mol Genet 2014; 23:6318-31. [PMID: 25055867 DOI: 10.1093/hmg/ddu350] [Citation(s) in RCA: 107] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Reduced expression of SMN protein causes spinal muscular atrophy (SMA), a neurodegenerative disorder leading to motor neuron dysfunction and loss. However, the molecular mechanisms by which SMN regulates neuronal dysfunction are not fully understood. Here, we report that reduced SMN protein level alters miRNA expression and distribution in neurons. In particular, miR-183 levels are increased in neurites of SMN-deficient neurons. We demonstrate that miR-183 regulates translation of mTor via direct binding to its 3' UTR. Interestingly, local axonal translation of mTor is reduced in SMN-deficient neurons, and this can be recovered by miR-183 inhibition. Finally, inhibition of miR-183 expression in the spinal cord of an SMA mouse model prolongs survival and improves motor function of Smn-mutant mice. Together, these observations suggest that axonal miRNAs and the mTOR pathway are previously unidentified molecular mechanisms contributing to SMA pathology.
Collapse
Affiliation(s)
- Min Jeong Kye
- Department of Neurology, The F. M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA, Institute of Human Genetics, Institute for Genetics and
| | - Emily D Niederst
- Department of Neurology, The F. M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Mary H Wertz
- Department of Neurology, The F. M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | | | - Bikem Akten
- Department of Neurology, The F. M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Katarzyna Z Dover
- Center for Motor Neuron Biology and Disease, Department of Pathology and Cell Biology and
| | - Miriam Peters
- Institute of Human Genetics, Institute for Genetics and, Center of Molecular Medicine Cologne, University of Cologne, Cologne, Germany
| | - Markus Riessland
- Institute of Human Genetics, Institute for Genetics and, Center of Molecular Medicine Cologne, University of Cologne, Cologne, Germany
| | - Pierre Neveu
- Kavli Institute for Theoretical Physics and, Neuroscience Research Institute, University of California at Santa Barbara, Santa Barbara, CA 93106, USA, Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, 69117, Heidelberg, Germany and
| | - Brunhilde Wirth
- Institute of Human Genetics, Institute for Genetics and, Center of Molecular Medicine Cologne, University of Cologne, Cologne, Germany
| | - Kenneth S Kosik
- Neuroscience Research Institute, University of California at Santa Barbara, Santa Barbara, CA 93106, USA
| | - S Pablo Sardi
- Genzyme, a Sanofi Company, Framingham, MA 01701, USA
| | - Umrao R Monani
- Center for Motor Neuron Biology and Disease, Department of Pathology and Cell Biology and, Department of Neurology, Columbia University Medical Center, New York, NY 10032, USA
| | | | - Mustafa Sahin
- Department of Neurology, The F. M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA,
| |
Collapse
|
34
|
Abstract
This review summarizes the current understanding of the role of nuclear bodies in regulating gene expression. The compartmentalization of cellular processes, such as ribosome biogenesis, RNA processing, cellular response to stress, transcription, modification and assembly of spliceosomal snRNPs, histone gene synthesis and nuclear RNA retention, has significant implications for gene regulation. These functional nuclear domains include the nucleolus, nuclear speckle, nuclear stress body, transcription factory, Cajal body, Gemini of Cajal body, histone locus body and paraspeckle. We herein review the roles of nuclear bodies in regulating gene expression and their relation to human health and disease.
Collapse
Affiliation(s)
| | - Cornelius F. Boerkoel
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +1-604-875-2157; Fax: +1-604-875-2376
| |
Collapse
|
35
|
Cauchi RJ. Gem depletion: amyotrophic lateral sclerosis and spinal muscular atrophy crossover. CNS Neurosci Ther 2014; 20:574-81. [PMID: 24645792 DOI: 10.1111/cns.12242] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2013] [Revised: 01/25/2014] [Accepted: 01/27/2014] [Indexed: 12/22/2022] Open
Abstract
The determining factor of spinal muscular atrophy (SMA), the most common motor neuron degenerative disease of childhood, is the survival motor neuron (SMN) protein. SMN and its Gemin associates form a complex that is indispensible for the biogenesis of small nuclear ribonucleoproteins (snRNPs), which constitute the building blocks of spliceosomes. It is as yet unclear whether a decreased capacity of SMN in snRNP assembly, and, hence, transcriptome abnormalities, account for the specific neuromuscular phenotype in SMA. Across metazoa, the SMN-Gemins complex concentrates in multiple nuclear gems that frequently neighbour or overlap Cajal bodies. The number of gems has long been known to be a faithful indicator of SMN levels, which are linked to SMA severity. Intriguingly, a flurry of recent studies have revealed that depletion of this nuclear structure is also a signature feature of amyotrophic lateral sclerosis (ALS), the most common adult-onset motor neuron disease. This review discusses such a surprising crossover in addition to highlighting the most recent work on the intricate world of spliceosome building, which seems to be at the heart of motor neuron physiology and survival.
Collapse
Affiliation(s)
- Ruben J Cauchi
- Department of Physiology and Biochemistry, University of Malta, Msida 2080, Malta
| |
Collapse
|
36
|
Zheng A, Chang W, Hou S, Zhang S, Cai H, Chen G, Lou R, Liu G. Unraveling molecular mechanistic differences in liver metabolism between lean and fat lines of Pekin duck (Anas platyrhynchos domestica): a proteomic study. J Proteomics 2014; 98:271-88. [PMID: 24412807 DOI: 10.1016/j.jprot.2013.12.021] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2013] [Revised: 12/18/2013] [Accepted: 12/22/2013] [Indexed: 11/18/2022]
Abstract
UNLABELLED Duck is one of the major poultry meat sources for human consumption. To satisfy different eating habits, lean and fat strains of Pekin ducks have been developed. The objective of this study was to determine the molecular mechanistic differences in liver metabolism between two duck strains. The liver proteome of the Pekin duck lines was compared on days 1, 14, 28, and 42 posthatching using 2-DE based proteomics. There was a different abundance of 76 proteins in the livers of the two duck lines. Fat ducks strongly expressed proteins related to pathways of glycolysis, ATP synthesis, and protein catabolism, suggesting enhanced fat deposition rather than protein retention. In contrast, highly expressed proteins in lean ducks improved protein anabolism and reduced protein catabolism, resulting in an enhancement of lean meat deposition. Along with the decrease in fat deposition, the immune system of the lean duck strain may be enhanced by enhanced expression of proteins involved in stress response, immune defense, and antioxidant functions. These results indicate that selection pressure has shaped the two duck lines differently resulting in different liver metabolic capacities. These observed variations between the two strains at the molecular level are matched with physiological changes in growth performance and meat production. This information may have beneficial impacts in areas such as genetic modification through the manipulation of target proteins or genes in specific pathways to improve the efficiency of duck meat production. BIOLOGICAL SIGNIFICANCE The objective of this study was to unravel molecular mechanistic differences in liver metabolism between lean and fat Pekin duck (Anas platyrhynchos domestica) strains. There was a different abundance of 76 proteins in the livers of the two duck lines. Enhanced protein expression in the fat ducks related to pathways of glycolysis, ATP synthesis and protein catabolism suggesting increased fat deposition rather than protein retention. In contrast, highly expressed proteins in the lean ducks facilitated protein deposition by increasing protein anabolism and reducing protein catabolism to enhance the lean meat percentage. Along with the decrease of fat deposition, the immunity of lean duck appeared to be enhanced by increased expression of proteins involved in stress response, defense and antioxidant function. This study provides potential target proteins or genes for further functional analysis and genetic manipulation to increase the efficiency of duck meat production and help satisfy the global demand for poultry meat.
Collapse
Affiliation(s)
- Aijuan Zheng
- Feed Research Institute, Key Laboratory of Feed Biotechnology, Ministry of Agriculture, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Wenhuan Chang
- Feed Research Institute, Key Laboratory of Feed Biotechnology, Ministry of Agriculture, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Shuisheng Hou
- Institute of Animal Sciences, State Key Laboratory of Animal Nutrition, Chinese Academy of Agricultural Sciences, Beijing 100193, China.
| | - Shu Zhang
- Feed Research Institute, Key Laboratory of Feed Biotechnology, Ministry of Agriculture, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Huiyi Cai
- Feed Research Institute, Key Laboratory of Feed Biotechnology, Ministry of Agriculture, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Guilan Chen
- Feed Research Institute, Key Laboratory of Feed Biotechnology, Ministry of Agriculture, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Ruiying Lou
- Feed Research Institute, Key Laboratory of Feed Biotechnology, Ministry of Agriculture, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Guohua Liu
- Feed Research Institute, Key Laboratory of Feed Biotechnology, Ministry of Agriculture, Chinese Academy of Agricultural Sciences, Beijing 100081, China.
| |
Collapse
|
37
|
The Gemin associates of survival motor neuron are required for motor function in Drosophila. PLoS One 2013; 8:e83878. [PMID: 24391840 PMCID: PMC3877121 DOI: 10.1371/journal.pone.0083878] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2013] [Accepted: 11/09/2013] [Indexed: 12/13/2022] Open
Abstract
Membership of the survival motor neuron (SMN) complex extends to nine factors, including the SMN protein, the product of the spinal muscular atrophy (SMA) disease gene, Gemins 2-8 and Unrip. The best-characterised function of this macromolecular machine is the assembly of the Sm-class of uridine-rich small nuclear ribonucleoprotein (snRNP) particles and each SMN complex member has a key role during this process. So far, however, only little is known about the function of the individual Gemin components in vivo. Here, we make use of the Drosophila model organism to uncover loss-of-function phenotypes of Gemin2, Gemin3 and Gemin5, which together with SMN form the minimalistic fly SMN complex. We show that ectopic overexpression of the dead helicase Gem3(ΔN) mutant or knockdown of Gemin3 result in similar motor phenotypes, when restricted to muscle, and in combination cause lethality, hence suggesting that Gem3(ΔN) overexpression mimics a loss-of-function. Based on the localisation pattern of Gem3(ΔN), we predict that the nucleus is the primary site of the antimorphic or dominant-negative mechanism of Gem3(ΔN)-mediated interference. Interestingly, phenotypes induced by human SMN overexpression in Drosophila exhibit similarities to those induced by overexpression of Gem3(ΔN). Through enhanced knockdown we also uncover a requirement of Gemin2, Gemin3 and Gemin5 for viability and motor behaviour, including locomotion as well as flight, in muscle. Notably, in the case of Gemin3 and Gemin5, such function also depends on adequate levels of the respective protein in neurons. Overall, these findings lead us to speculate that absence of any one member is sufficient to arrest the SMN-Gemins complex function in a nucleocentric pathway, which is critical for motor function in vivo.
Collapse
|
38
|
Tiziano FD, Melki J, Simard LR. Solving the puzzle of spinal muscular atrophy: what are the missing pieces? Am J Med Genet A 2013; 161A:2836-45. [PMID: 24124019 DOI: 10.1002/ajmg.a.36251] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2013] [Accepted: 08/30/2013] [Indexed: 12/13/2022]
Abstract
Spinal muscular atrophy (SMA) is an autosomal recessive, lower motor neuron disease. Clinical heterogeneity is pervasive: three infantile (type I-III) and one adult-onset (type IV) forms are recognized. Type I SMA is the most common genetic cause of death in infancy and accounts for about 50% of all patients with SMA. Most forms of SMA are caused by mutations of the survival motor neuron (SMN1) gene. A second gene that is 99% identical to SMN1 (SMN2) is located in the same region. The only functionally relevant difference between the two genes identified to date is a C → T transition in exon 7 of SMN2, which determines an alternative spliced isoform that predominantly excludes exon 7. Thus, SMN2 genes do not produce sufficient full length SMN protein to prevent the onset of the disease. Since the identification of the causative mutation, biomedical research of SMA has progressed by leaps and bounds: from clues on the function of SMN protein, to the development of different models of the disease, to the identification of potential treatments, some of which are currently in human trials. The aim of this review is to elucidate the current state of knowledge, emphasizing how close we are to the solution of the puzzle that is SMA, and, more importantly, to highlight the missing pieces of this puzzle. Filling in these gaps in our knowledge will likely accelerate the development and delivery of efficient treatments for SMA patients and be a prerequisite towards achieving our final goal, the cure of SMA.
Collapse
|
39
|
The functional interactome landscape of the human histone deacetylase family. Mol Syst Biol 2013; 9:672. [PMID: 23752268 PMCID: PMC3964310 DOI: 10.1038/msb.2013.26] [Citation(s) in RCA: 218] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2013] [Accepted: 04/29/2013] [Indexed: 12/22/2022] Open
Abstract
This study presents the first global protein interaction network for all 11 human HDACs in T cells and an integrative mass spectrometry approach for profiling relative interaction stability within isolated protein complexes. ![]()
T-cell lines stably expressing each of the human HDACs (1 - 11), C-terminally tagged with both EGFP and FLAG, were generated using retroviral transduction. Affinity purification coupled to mass spectrometry-based proteomics (AP-MS) was used to build the first global protein interaction network for all eleven human HDACs in T cells. An optimized label free AP-MS and computational workflow was developed for profiling relative interaction stability among isolated protein complexes. HDAC11 is a member of the “survival of motor neuron” protein complex with a functional role in mRNA splicing.
Histone deacetylases (HDACs) are a diverse family of essential transcriptional regulatory enzymes, that function through the spatial and temporal recruitment of protein complexes. As the composition and regulation of HDAC complexes are only partially characterized, we built the first global protein interaction network for all 11 human HDACs in T cells. Integrating fluorescence microscopy, immunoaffinity purifications, quantitative mass spectrometry, and bioinformatics, we identified over 200 unreported interactions for both well-characterized and lesser-studied HDACs, a subset of which were validated by orthogonal approaches. We establish HDAC11 as a member of the survival of motor neuron complex and pinpoint a functional role in mRNA splicing. We designed a complementary label-free and metabolic-labeling mass spectrometry-based proteomics strategy for profiling interaction stability among different HDAC classes, revealing that HDAC1 interactions within chromatin-remodeling complexes are largely stable, while transcription factors preferentially exist in rapid equilibrium. Overall, this study represents a valuable resource for investigating HDAC functions in health and disease, encompassing emerging themes of HDAC regulation in cell cycle and RNA processing and a deeper functional understanding of HDAC complex stability.
Collapse
|
40
|
Sousounis K, Looso M, Maki N, Ivester CJ, Braun T, Tsonis PA. Transcriptome analysis of newt lens regeneration reveals distinct gradients in gene expression patterns. PLoS One 2013; 8:e61445. [PMID: 23613853 PMCID: PMC3628982 DOI: 10.1371/journal.pone.0061445] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2013] [Accepted: 03/09/2013] [Indexed: 12/11/2022] Open
Abstract
Regeneration of the lens in newts is quite a unique process. The lens is removed in its entirety and regeneration ensues from the pigment epithelial cells of the dorsal iris via transdifferentiation. The same type of cells from the ventral iris are not capable of regenerating a lens. It is, thus, expected that differences between dorsal and ventral iris during the process of regeneration might provide important clues pertaining to the mechanism of regeneration. In this paper, we employed next generation RNA-seq to determine gene expression patterns during lens regeneration in Notophthalmus viridescens. The expression of more than 38,000 transcripts was compared between dorsal and ventral iris. Although very few genes were found to be dorsal- or ventral-specific, certain groups of genes were up-regulated specifically in the dorsal iris. These genes are involved in cell cycle, gene regulation, cytoskeleton and immune response. In addition, the expression of six highly regulated genes, TBX5, FGF10, UNC5B, VAX2, NR2F5, and NTN1, was verified using qRT-PCR. These graded gene expression patterns provide insight into the mechanism of lens regeneration, the markers that are specific to dorsal or ventral iris, and layout a map for future studies in the field.
Collapse
Affiliation(s)
- Konstantinos Sousounis
- Department of Biology and Center for Tissue Regeneration and Engineering at Dayton, University of Dayton, Dayton, Ohio, United States of America
| | - Mario Looso
- Department of Bioinformatics, Max-Planck-Institute for Heart and Lung Research, Bad Nauheim, Germany
| | - Nobuyasu Maki
- Department of Biology and Center for Tissue Regeneration and Engineering at Dayton, University of Dayton, Dayton, Ohio, United States of America
| | - Clifford J. Ivester
- Department of Biology and Center for Tissue Regeneration and Engineering at Dayton, University of Dayton, Dayton, Ohio, United States of America
| | - Thomas Braun
- Department of Cardiac Development and Remodeling, Max-Planck-Institute for Heart and Lung Research, Bad Nauheim, Germany
- * E-mail: (TB); (PAT)
| | - Panagiotis A. Tsonis
- Department of Biology and Center for Tissue Regeneration and Engineering at Dayton, University of Dayton, Dayton, Ohio, United States of America
- * E-mail: (TB); (PAT)
| |
Collapse
|
41
|
Foster MW, Thompson JW, Forrester MT, Sha Y, McMahon TJ, Bowles DE, Moseley MA, Marshall HE. Proteomic analysis of the NOS2 interactome in human airway epithelial cells. Nitric Oxide 2013; 34:37-46. [PMID: 23438482 DOI: 10.1016/j.niox.2013.02.079] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2012] [Revised: 02/07/2013] [Accepted: 02/08/2013] [Indexed: 01/22/2023]
Abstract
The cytokine-inducible isoform of nitric oxide synthase (NOS2) is constitutively expressed in human respiratory epithelia and is upregulated in inflammatory lung disease. Here, we sought to better define the protein interactions that may be important for NOS2 activity and stability, as well as to identify potential targets of NOS2-derived NO, in the respiratory epithelium. We overexpressed Flag-tagged, catalytically-inactive NOS2 in A549 cells and used mass spectrometry to qualitatively identify NOS2 co-immunoprecipitating proteins. Stable isotope labeling of amino acids in cell culture (SILAC) was used to quantify the coordinate effects of cytokine stimulation on NOS2-protein interactions. Multi-protein networks dominated the NOS2 interactome, and cytokine-inducible interactions with allosteric activators and with the ubiquitin-proteasome system were correlated with cytokine-dependent increases in NO metabolites and in NOS2 ubiquitination. The ubiquitin ligase scaffolding protein, FBXO45, was identified as a novel, direct NOS2 interactor. Similar to the SPRY domain-containing SOCS box (SPSB) proteins, FBXO45 requires Asn27 in the (23)DINNN(27) motif of NOS2 for its interaction. However, FBXO45 is unique from the SPSBs in that it recruits a distinct E3 ligase complex containing MYCBP2 and SKP1. Collectively, these findings demonstrate the general utility of interaction proteomics for defining new aspects of NOS2 physiology.
Collapse
Affiliation(s)
- Matthew W Foster
- Division of Pulmonary, Allergy and Critical Care Medicine, Duke University Medical Centers, Durham, NC 27710, United States.
| | | | | | | | | | | | | | | |
Collapse
|
42
|
Anderton RS, Meloni BP, Mastaglia FL, Boulos S. Spinal muscular atrophy and the antiapoptotic role of survival of motor neuron (SMN) protein. Mol Neurobiol 2013; 47:821-32. [PMID: 23315303 DOI: 10.1007/s12035-013-8399-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2012] [Accepted: 01/03/2013] [Indexed: 11/26/2022]
Abstract
Spinal muscular atrophy (SMA) is a devastating and often fatal neurodegenerative disease that affects spinal motor neurons and leads to progressive muscle wasting and paralysis. The survival of motor neuron (SMN) gene is mutated or deleted in most forms of SMA, which results in a critical reduction in SMN protein. Motor neurons appear particularly vulnerable to reduced SMN protein levels. Therefore, understanding the functional role of SMN in protecting motor neurons from degeneration is an essential prerequisite for the design of effective therapies for SMA. To this end, there is increasing evidence indicating a key regulatory antiapoptotic role for the SMN protein that is important in motor neuron survival. The aim of this review is to highlight key findings that support an antiapoptotic role for SMN in modulating cell survival and raise possibilities for new therapeutic approaches.
Collapse
Affiliation(s)
- Ryan S Anderton
- Centre for Neuromuscular and Neurological Disorders, University of Western Australia and Australian Neuromuscular Research Institute, Nedlands, Western Australia, Australia.
| | | | | | | |
Collapse
|
43
|
Sabra M, Texier P, El Maalouf J, Lomonte P. The tudor protein survival motor neuron (SMN) is a chromatin-binding protein that interacts with methylated histone H3 lysine 79. J Cell Sci 2013; 126:3664-77. [DOI: 10.1242/jcs.126003] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Spinal muscular atrophy (SMA) is a muscular disease characterized by the death of motoneurons, and is a major genetic cause of infant mortality. Mutations in the SMN1 gene, which encodes the protein survival motor neuron (SMN), are responsible for the disease due to compensation deficit. SMN belongs to the Tudor domain protein family, whose members are known to interact with methylated arginine (R) or lysine (K) residues. SMN has well-defined roles in the metabolism of small non-coding ribonucleoproteins (snRNPs) and spliceosome activity. We previously showed that SMN relocated to damaged interphase centromeres, together with the Cajal body-associated proteins coilin and fibrillarin, during the so-called interphase centromere damage response (iCDR). Here we reveal that SMN is a chromatin-binding protein that specifically interacts with methylated histone H3K79, a gene expression- and splicing-associated histone modification. SMN relocation to damaged centromeres requires its functional Tudor domain and activity of the H3K79 methyltransferase DOT1-L. In vitro pull-down assays showed that SMN interacts with H3K79me1,2 via its functional Tudor domain. Chromatin immunoprecipitation confirmed that SMN binds to H3K79me1,2-containing chromatin in iCDR-induced cells. These data reveal a novel SMN property in the detection of specific chromatin modifications, and shed new light on the involvement of a putative epigenetic dimension to the occurrence of SMA.
Collapse
|
44
|
Piazzon N, Schlotter F, Lefebvre S, Dodré M, Méreau A, Soret J, Besse A, Barkats M, Bordonné R, Branlant C, Massenet S. Implication of the SMN complex in the biogenesis and steady state level of the signal recognition particle. Nucleic Acids Res 2012; 41:1255-72. [PMID: 23221635 PMCID: PMC3553995 DOI: 10.1093/nar/gks1224] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Spinal muscular atrophy is a severe motor neuron disease caused by reduced levels of the ubiquitous Survival of MotoNeurons (SMN) protein. SMN is part of a complex that is essential for spliceosomal UsnRNP biogenesis. Signal recognition particle (SRP) is a ribonucleoprotein particle crucial for co-translational targeting of secretory and membrane proteins to the endoplasmic reticulum. SRP biogenesis is a nucleo-cytoplasmic multistep process in which the protein components, except SRP54, assemble with 7S RNA in the nucleolus. Then, SRP54 is incorporated after export of the pre-particle into the cytoplasm. The assembly factors necessary for SRP biogenesis remain to be identified. Here, we show that 7S RNA binds to purified SMN complexes in vitro and that SMN complexes associate with SRP in cellular extracts. We identified the RNA determinants required. Moreover, we report a specific reduction of 7S RNA levels in the spinal cord of SMN-deficient mice, and in a Schizosaccharomyces pombe strain carrying a temperature-degron allele of SMN. Additionally, microinjected antibodies directed against SMN or Gemin2 interfere with the association of SRP54 with 7S RNA in Xenopus laevis oocytes. Our data show that reduced levels of the SMN protein lead to defect in SRP steady-state level and describe the SMN complex as the first identified cellular factor required for SRP biogenesis.
Collapse
Affiliation(s)
- Nathalie Piazzon
- Laboratoire ARN-RNP structure-fonction-maturation, Enzymologie Moléculaire et Structurale (AREMS), Nancy Université-CNRS, UMR 7214, FR 3209, Faculté de Médecine de Nancy, BP 184, 9 avenue de la forêt de Haye, 54506 Vandoeuvre-les-Nancy Cedex, France
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
45
|
Donnelly EM, Boulis NM. Update on gene and stem cell therapy approaches for spinal muscular atrophy. Expert Opin Biol Ther 2012; 12:1463-71. [PMID: 22849423 DOI: 10.1517/14712598.2012.711306] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
INTRODUCTION Spinal muscular atrophy (SMA) is the leading genetic cause of pediatric death to which at present there is no effective therapeutic. The genetic defect is well characterized as a mutation in exon 7 of the survival of motor neuron (SMN) gene. The current gene therapy approach focuses on two main methodologies, the replacement of SMN1 or augmentation of SMN2 readthrough. The most promising of the current work focuses on the delivery of SMN via AAV9 vectors via intravenous delivery. AREAS COVERED In the review the authors examine the current research in the field of stem cell and gene therapy approaches for SMA. Also focusing on delivery methods, timing of administration and general caveats that must be considered with translational work for SMA. EXPERT OPINION Gene therapy currently offers the most promising avenue of research for a successful therapeutic for SMA. There are many important practical and ethical considerations which must be carefully considered when dealing with clinical trial in infants such as the invasiveness of the surgery, the correct patient cohort and the potential risks.
Collapse
|
46
|
Liu J, Liu J, Wei M, He Y, Liao B, Liao G, Li H, Huang J. Genetic variants in the microRNA machinery gene GEMIN4 are associated with risk of prostate cancer: a case-control study of the Chinese Han population. DNA Cell Biol 2012; 31:1296-302. [PMID: 22506892 DOI: 10.1089/dna.2011.1600] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Single-nucleotide polymorphisms located in the microRNA biogenesis pathway could alter the risk for developing prostate cancer. The present study was intended to identify common genetic variants responsible for prostate cancer susceptibility in the GEMIN4 gene. The high-resolution melting method was used to genotype seven polymorphisms (rs7813, rs4968104, rs3744741, rs2740348, rs1062923, rs910925, and rs910924) in the GEMIN4 gene in 300 prostate cancer patients and 244 matched controls. The encouraging discovery in this study was in the rs2740348. Patients carrying the variant heterozygote GC genotype in the rs2740348 were at a 36% decreased risk of prostate cancer (odds ratio [OR] = 0.64; 95% confidence interval [CI] = 0.42, 0.99). Similarly, this variant allele carrier showed significant risk for prostate cancer (OR = 0.64). In addition, subjects carrying the homozygote TT genotype in the rs7813 had a significantly increased risk of prostate cancer (OR = 2.53, 95% CI = 1.07, 6.28). Two common haplotypes were found to be associated with decreased risk of prostate cancer. In the subgroup analysis, higher risk of more severity of prostate cancer (clinical stage III and IV) was observed in individuals with the rs7813 TT genotype (OR = 2.64, 95% CI = 1.02, 7.64), while lower risk of more severity of prostate cancer was observed in individuals with the rs3744741 T allele (OR = 0.69, 95% CI = 0.50, 0.96). Overall, our study provides substantial support for the association between the GEMIN4 gene and the risk of prostate cancer.
Collapse
Affiliation(s)
- Jiaming Liu
- West China School of Medicine/West China Hospital, Sichuan University, Chengdu, Sichuan Province, PR China
| | | | | | | | | | | | | | | |
Collapse
|
47
|
Renvoisé B, Quérol G, Verrier ER, Burlet P, Lefebvre S. A role for protein phosphatase PP1γ in SMN complex formation and subnuclear localization to Cajal bodies. J Cell Sci 2012; 125:2862-74. [PMID: 22454514 DOI: 10.1242/jcs.096255] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
The spinal muscular atrophy (SMA) gene product SMN forms with gem-associated protein 2-8 (Gemin2-8) and unrip (also known as STRAP) the ubiquitous survival motor neuron (SMN) complex, which is required for the assembly of spliceosomal small nuclear ribonucleoproteins (snRNPs), their nuclear import and their localization to subnuclear domain Cajal bodies (CBs). The concentration of the SMN complex and snRNPs in CBs is reduced upon SMN deficiency in SMA cells. Subcellular localization of the SMN complex is regulated in a phosphorylation-dependent manner and the precise mechanisms remain poorly understood. Using co-immunoprecipitation in HeLa cell extracts and in vitro protein binding assays, we show here that the SMN complex and its component Gemin8 interact directly with protein phosphatase PP1γ. Overexpression of Gemin8 in cells increases the number of CBs and results in targeting of PP1γ to CBs. Moreover, depletion of PP1γ by RNA interference enhances the localization of the SMN complex and snRNPs to CBs. Consequently, the interaction between SMN and Gemin8 increases in cytoplasmic and nuclear extracts of PP1γ-depleted cells. Two-dimensional protein gel electrophoresis revealed that SMN is hyperphosphorylated in nuclear extracts of PP1γ-depleted cells and expression of PP1γ restores these isoforms. Notably, SMN deficiency in SMA leads to the aberrant subcellular localization of Gemin8 and PP1γ in the atrophic skeletal muscles, suggesting that the function of PP1γ is likely to be affected in disease. Our findings reveal a role of PP1γ in the formation of the SMN complex and the maintenance of CB integrity. Finally, we propose Gemin8 interaction with PP1γ as a target for therapeutic intervention in SMA.
Collapse
Affiliation(s)
- Benoît Renvoisé
- Laboratoire de Biologie Cellulaire des Membranes, Programme de Biologie Cellulaire, Institut Jacques-Monod, UMR 7592 CNRS, Université Paris Diderot, Sorbonne Paris Cité, 15 rue Hélène Brion, 75205 Paris cedex 13, France
| | | | | | | | | |
Collapse
|
48
|
Makarov EM, Owen N, Bottrill A, Makarova OV. Functional mammalian spliceosomal complex E contains SMN complex proteins in addition to U1 and U2 snRNPs. Nucleic Acids Res 2011; 40:2639-52. [PMID: 22110043 PMCID: PMC3315330 DOI: 10.1093/nar/gkr1056] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Spliceosomes remove introns from primary gene transcripts. They assemble de novo on each intron through a series of steps that involve the incorporation of five snRNP particles and multiple non-snRNP proteins. In mammals, all the intermediate complexes have been characterized on one transcript (MINX), with the exception of the very first, complex E. We have purified this complex by two independent procedures using antibodies to either U1-A or PRPF40A proteins, which are known to associate at an early stage of assembly. We demonstrate that the purified complexes are functional in splicing using commitment assays. These complexes contain components expected to be in the E complex and a number of previously unrecognized factors, including survival of motor neurons (SMN) and proteins of the SMN-associated complex. Depletion of the SMN complex proteins from nuclear extracts inhibits formation of the E complex and causes non-productive complexes to accumulate. This suggests that the SMN complex stabilizes the association of U1 and U2 snRNPs with pre-mRNA. In addition, the antibody to PRPF40A precipitated U2 snRNPs from nuclear extracts, indicating that PRPF40A associates with U2 snRNPs.
Collapse
Affiliation(s)
- Evgeny M Makarov
- Department of Biochemistry, University of Leicester, Leicester LE1 9HN, UK
| | | | | | | |
Collapse
|
49
|
A role for SMN exon 7 splicing in the selective vulnerability of motor neurons in spinal muscular atrophy. Mol Cell Biol 2011; 32:126-38. [PMID: 22037760 DOI: 10.1128/mcb.06077-11] [Citation(s) in RCA: 89] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Spinal muscular atrophy (SMA) is an inherited motor neuron disease caused by homozygous loss of the Survival Motor Neuron 1 (SMN1) gene. In the absence of SMN1, inefficient inclusion of exon 7 in transcripts from the nearly identical SMN2 gene results in ubiquitous SMN decrease but selective motor neuron degeneration. Here we investigated whether cell type-specific differences in the efficiency of exon 7 splicing contribute to the vulnerability of SMA motor neurons. We show that normal motor neurons express markedly lower levels of full-length SMN mRNA from SMN2 than do other cells in the spinal cord. This is due to inefficient exon 7 splicing that is intrinsic to motor neurons under normal conditions. We also find that SMN depletion in mammalian cells decreases exon 7 inclusion through a negative feedback loop affecting the splicing of its own mRNA. This mechanism is active in vivo and further decreases the efficiency of exon 7 inclusion specifically in motor neurons of severe-SMA mice. Consistent with expression of lower levels of full-length SMN, we find that SMN-dependent downstream molecular defects are exacerbated in SMA motor neurons. These findings suggest a mechanism to explain the selective vulnerability of motor neurons to loss of SMN1.
Collapse
|
50
|
Zhang R, So BR, Li P, Yong J, Glisovic T, Wan L, Dreyfuss G. Structure of a key intermediate of the SMN complex reveals Gemin2's crucial function in snRNP assembly. Cell 2011; 146:384-95. [PMID: 21816274 PMCID: PMC3160754 DOI: 10.1016/j.cell.2011.06.043] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2011] [Revised: 05/10/2011] [Accepted: 06/27/2011] [Indexed: 01/10/2023]
Abstract
The SMN complex mediates the assembly of heptameric Sm protein rings on small nuclear RNAs (snRNAs), which are essential for snRNP function. Specific Sm core assembly depends on Sm proteins and snRNA recognition by SMN/Gemin2- and Gemin5-containing subunits, respectively. The mechanism by which the Sm proteins are gathered while preventing illicit Sm assembly on non-snRNAs is unknown. Here, we describe the 2.5 Å crystal structure of Gemin2 bound to SmD1/D2/F/E/G pentamer and SMN's Gemin2-binding domain, a key assembly intermediate. Remarkably, through its extended conformation, Gemin2 wraps around the crescent-shaped pentamer, interacting with all five Sm proteins, and gripping its bottom and top sides and outer perimeter. Gemin2 reaches into the RNA-binding pocket, preventing RNA binding. Interestingly, SMN-Gemin2 interaction is abrogated by a spinal muscular atrophy (SMA)-causing mutation in an SMN helix that mediates Gemin2 binding. These findings provide insight into SMN complex assembly and specificity, linking snRNP biogenesis and SMA pathogenesis.
Collapse
Affiliation(s)
- Rundong Zhang
- Howard Hughes Medical Institute, University of Pennsylvania School of Medicine, Philadelphia, PA 19104-6148, USA
| | | | | | | | | | | | | |
Collapse
|