1
|
Zheng X, Chen J, Deng M, Ning K, Peng Y, Liu Z, Li X, Zhou Z, Tang H, Li Y, Kang T, Liu Z. G3BP1 and SLU7 Jointly Promote Immune Evasion by Downregulating MHC-I via PI3K/Akt Activation in Bladder Cancer. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024; 11:e2305922. [PMID: 38084438 PMCID: PMC10870071 DOI: 10.1002/advs.202305922] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Revised: 11/13/2023] [Indexed: 02/17/2024]
Abstract
Immune checkpoint inhibitors (ICIs) show promise as second-line treatment for advanced bladder cancer (BLCA); however, their responsiveness is limited by the immune evasion mechanisms in tumor cells. This study conduct a Cox regression analysis to screen mRNA-binding proteins and reveals an association between Ras GTPase-activating protein-binding protein 1 (G3BP1) and diminished effectiveness of ICI therapy in patients with advanced BLCA. Subsequent investigation demonstrates that G3BP1 enhances immune evasion in BLCA cells by downregulating major histocompatibility complex class I (MHC-I) through phosphoinositide 3-kinase (PI3K)/Akt signaling activation. Mechanistically, G3BP1 interacts with splicing factor synergistic lethal with U5 snRNA 7 (SLU7) to form a complex with poly(A)-binding protein cytoplasmic 1 and eukaryotic translation initiation factor 4 gamma 1. This complex stabilizes the closed-loop structure of the mRNAs of class IA PI3Ks and consequently facilitates their translation and stabilization, thereby activating PI3K/Akt signaling to downregulate MHC-I. Consistently, targeting G3BP1 with epigallocatechin gallate (EGCG) impedes immune evasion and sensitizes BLCA cells to anti-programmed cell death (PD)-1 antibodies in mice. Thus, G3BP1 and SLU7 collaboratively contribute to immune evasion in BLCA, indicating that EGCG is a precision therapeutic agent to enhance the effectiveness of anti-PD-1 therapy.
Collapse
Affiliation(s)
- Xianchong Zheng
- Department of UrologySun Yat‐sen University Cancer CenterGuangzhou510060P. R. China
- State Key Laboratory of Oncology in South ChinaGuangdong Provincial Clinical Research Center for CancerSun Yat‐sen University Cancer CenterGuangzhou510060P. R. China
| | - Jiawei Chen
- Department of UrologySun Yat‐sen University Cancer CenterGuangzhou510060P. R. China
- State Key Laboratory of Oncology in South ChinaGuangdong Provincial Clinical Research Center for CancerSun Yat‐sen University Cancer CenterGuangzhou510060P. R. China
- Department of UrologyShunde HospitalSouthern Medical University (The First People's Hospital of Shunde Foshan)Foshan528000P. R. China
| | - Minhua Deng
- Department of UrologySun Yat‐sen University Cancer CenterGuangzhou510060P. R. China
- State Key Laboratory of Oncology in South ChinaGuangdong Provincial Clinical Research Center for CancerSun Yat‐sen University Cancer CenterGuangzhou510060P. R. China
| | - Kang Ning
- Department of UrologySun Yat‐sen University Cancer CenterGuangzhou510060P. R. China
- State Key Laboratory of Oncology in South ChinaGuangdong Provincial Clinical Research Center for CancerSun Yat‐sen University Cancer CenterGuangzhou510060P. R. China
| | - Yulu Peng
- Department of UrologySun Yat‐sen University Cancer CenterGuangzhou510060P. R. China
- State Key Laboratory of Oncology in South ChinaGuangdong Provincial Clinical Research Center for CancerSun Yat‐sen University Cancer CenterGuangzhou510060P. R. China
| | - Zhenhua Liu
- Department of UrologySun Yat‐sen University Cancer CenterGuangzhou510060P. R. China
- State Key Laboratory of Oncology in South ChinaGuangdong Provincial Clinical Research Center for CancerSun Yat‐sen University Cancer CenterGuangzhou510060P. R. China
| | - Xiangdong Li
- Department of UrologySun Yat‐sen University Cancer CenterGuangzhou510060P. R. China
| | - Zhaohui Zhou
- Department of UrologySun Yat‐sen University Cancer CenterGuangzhou510060P. R. China
- State Key Laboratory of Oncology in South ChinaGuangdong Provincial Clinical Research Center for CancerSun Yat‐sen University Cancer CenterGuangzhou510060P. R. China
| | - Huancheng Tang
- Department of UrologySun Yat‐sen University Cancer CenterGuangzhou510060P. R. China
- State Key Laboratory of Oncology in South ChinaGuangdong Provincial Clinical Research Center for CancerSun Yat‐sen University Cancer CenterGuangzhou510060P. R. China
| | - Yaoying Li
- State Key Laboratory of Oncology in South ChinaGuangdong Provincial Clinical Research Center for CancerSun Yat‐sen University Cancer CenterGuangzhou510060P. R. China
| | - Tiebang Kang
- State Key Laboratory of Oncology in South ChinaGuangdong Provincial Clinical Research Center for CancerSun Yat‐sen University Cancer CenterGuangzhou510060P. R. China
| | - Zhuowei Liu
- Department of UrologySun Yat‐sen University Cancer CenterGuangzhou510060P. R. China
- State Key Laboratory of Oncology in South ChinaGuangdong Provincial Clinical Research Center for CancerSun Yat‐sen University Cancer CenterGuangzhou510060P. R. China
- Department of UrologySun Yat‐sen University Cancer Center Gansu HospitalLanzhou730000P. R. China
| |
Collapse
|
2
|
Goswami B, Nag S, Ray PS. Fates and functions of RNA-binding proteins under stress. WILEY INTERDISCIPLINARY REVIEWS. RNA 2023:e1825. [PMID: 38014833 DOI: 10.1002/wrna.1825] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2023] [Revised: 10/03/2023] [Accepted: 10/30/2023] [Indexed: 11/29/2023]
Abstract
Exposure to stress activates a well-orchestrated set of changes in gene expression programs that allow the cell to cope with and adapt to the stress, or undergo programmed cell death. RNA-protein interactions, mediating all aspects of post-transcriptional regulation of gene expression, play crucial roles in cellular stress responses. RNA-binding proteins (RBPs), which interact with sequence/structural elements in RNAs to control the steps of RNA metabolism, have therefore emerged as central regulators of post-transcriptional responses to stress. Following exposure to a variety of stresses, the dynamic alterations in the RNA-protein interactome enable cells to respond to intracellular or extracellular perturbations by causing changes in mRNA splicing, polyadenylation, stability, translation, and localization. As RBPs play a central role in determining the cellular proteome both qualitatively and quantitatively, it has become increasingly evident that their abundance, availability, and functions are also highly regulated in response to stress. Exposure to stress initiates a series of signaling cascades that converge on post-translational modifications (PTMs) of RBPs, resulting in changes in their subcellular localization, association with stress granules, extracellular export, proteasomal degradation, and RNA-binding activities. These alterations in the fate and function of RBPs directly impact their post-transcriptional regulatory roles in cells under stress. Adopting the ubiquitous RBP HuR as a prototype, three scenarios illustrating the changes in nuclear-cytoplasmic localization, RNA-binding activity, export and degradation of HuR in response to inflammation, genotoxic stress, and heat shock depict the complex and interlinked regulatory mechanisms that control the fate and functions of RBPs under stress. This article is categorized under: RNA Interactions with Proteins and Other Molecules > Protein-RNA Interactions: Functional Implications.
Collapse
Affiliation(s)
- Binita Goswami
- Department of Biological Sciences, Indian Institute of Science Education and Research, Mohanpur, West Bengal, India
| | - Sharanya Nag
- Department of Biological Sciences, Indian Institute of Science Education and Research, Mohanpur, West Bengal, India
| | - Partho Sarothi Ray
- Department of Biological Sciences, Indian Institute of Science Education and Research, Mohanpur, West Bengal, India
| |
Collapse
|
3
|
Gárate-Rascón M, Recalde M, Rojo C, Fernández-Barrena MG, Ávila MA, Arechederra M, Berasain C. SLU7: A New Hub of Gene Expression Regulation—From Epigenetics to Protein Stability in Health and Disease. Int J Mol Sci 2022; 23:ijms232113411. [PMID: 36362191 PMCID: PMC9658179 DOI: 10.3390/ijms232113411] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Revised: 10/28/2022] [Accepted: 10/31/2022] [Indexed: 11/06/2022] Open
Abstract
SLU7 (Splicing factor synergistic lethal with U5 snRNA 7) was first identified as a splicing factor necessary for the correct selection of 3′ splice sites, strongly impacting on the diversity of gene transcripts in a cell. More recent studies have uncovered new and non-redundant roles of SLU7 as an integrative hub of different levels of gene expression regulation, including epigenetic DNA remodeling, modulation of transcription and protein stability. Here we review those findings, the multiple factors and mechanisms implicated as well as the cellular functions affected. For instance, SLU7 is essential to secure liver differentiation, genome integrity acting at different levels and a correct cell cycle progression. Accordingly, the aberrant expression of SLU7 could be associated with human diseases including cancer, although strikingly, it is an essential survival factor for cancer cells. Finally, we discuss the implications of SLU7 in pathophysiology, with particular emphasis on the progression of liver disease and its possible role as a therapeutic target in human cancer.
Collapse
Affiliation(s)
- María Gárate-Rascón
- Program of Hepatology, Center for Applied Medical Research (CIMA), University of Navarra, Avda. Pio XII, n55, 31008 Pamplona, Spain
| | - Miriam Recalde
- Program of Hepatology, Center for Applied Medical Research (CIMA), University of Navarra, Avda. Pio XII, n55, 31008 Pamplona, Spain
| | - Carla Rojo
- Program of Hepatology, Center for Applied Medical Research (CIMA), University of Navarra, Avda. Pio XII, n55, 31008 Pamplona, Spain
| | - Maite G. Fernández-Barrena
- Program of Hepatology, Center for Applied Medical Research (CIMA), University of Navarra, Avda. Pio XII, n55, 31008 Pamplona, Spain
- IdiSNA, Navarra Institute for Health Research, 31008 Pamplona, Spain
- National Institute for the Study of Liver and Gastrointestinal Diseases (CIBERehd, Carlos III Health Institute), 28029 Madrid, Spain
| | - Matías A. Ávila
- Program of Hepatology, Center for Applied Medical Research (CIMA), University of Navarra, Avda. Pio XII, n55, 31008 Pamplona, Spain
- IdiSNA, Navarra Institute for Health Research, 31008 Pamplona, Spain
- National Institute for the Study of Liver and Gastrointestinal Diseases (CIBERehd, Carlos III Health Institute), 28029 Madrid, Spain
| | - María Arechederra
- Program of Hepatology, Center for Applied Medical Research (CIMA), University of Navarra, Avda. Pio XII, n55, 31008 Pamplona, Spain
- IdiSNA, Navarra Institute for Health Research, 31008 Pamplona, Spain
- National Institute for the Study of Liver and Gastrointestinal Diseases (CIBERehd, Carlos III Health Institute), 28029 Madrid, Spain
| | - Carmen Berasain
- Program of Hepatology, Center for Applied Medical Research (CIMA), University of Navarra, Avda. Pio XII, n55, 31008 Pamplona, Spain
- IdiSNA, Navarra Institute for Health Research, 31008 Pamplona, Spain
- National Institute for the Study of Liver and Gastrointestinal Diseases (CIBERehd, Carlos III Health Institute), 28029 Madrid, Spain
- Correspondence: ; Tel.: +34-948-194700; Fax: +34-948-194717
| |
Collapse
|
4
|
Douet-Guilbert N, Soubise B, Bernard DG, Troadec MB. Cytogenetic and Genetic Abnormalities with Diagnostic Value in Myelodysplastic Syndromes (MDS): Focus on the Pre-Messenger RNA Splicing Process. Diagnostics (Basel) 2022; 12:1658. [PMID: 35885562 PMCID: PMC9320363 DOI: 10.3390/diagnostics12071658] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Revised: 06/28/2022] [Accepted: 06/29/2022] [Indexed: 12/19/2022] Open
Abstract
Myelodysplastic syndromes (MDS) are considered to be diseases associated with splicing defects. A large number of genes involved in the pre-messenger RNA splicing process are mutated in MDS. Deletion of 5q and 7q are of diagnostic value, and those chromosome regions bear the numbers of splicing genes potentially deleted in del(5q) and del(7q)/-7 MDS. In this review, we present the splicing genes already known or suspected to be implicated in MDS pathogenesis. First, we focus on the splicing genes located on chromosome 5 (HNRNPA0, RBM27, RBM22, SLU7, DDX41), chromosome 7 (LUC7L2), and on the SF3B1 gene since both chromosome aberrations and the SF3B1 mutation are the only genetic abnormalities in splicing genes with clear diagnostic values. Then, we present and discuss other splicing genes that are showing a prognostic interest (SRSF2, U2AF1, ZRSR2, U2AF2, and PRPF8). Finally, we discuss the haploinsufficiency of splicing genes, especially from chromosomes 5 and 7, the important amplifier process of splicing defects, and the cumulative and synergistic effect of splicing genes defects in the MDS pathogenesis. At the time, when many authors suggest including the sequencing of some splicing genes to improve the diagnosis and the prognosis of MDS, a better understanding of these cooperative defects is needed.
Collapse
Grants
- comités 16, 22, 29, 35, 56, 41 and 85 Ligue Régionale contre le cancer (comités 16, 22, 29, 35, 56, 41 and 85)
- 2021-2022 Association Halte au Cancer
- 2020-2022 Association Gaétan Saleün
- 2020-2022 Association connaître et combattre la myélodysplasie
- 2021-2022 le Collectif Agora de Guilers
- 2021-2023 Association Fondation de l'Avenir
- 2021-2023 fonds INNOVEO Brest
Collapse
Affiliation(s)
- Nathalie Douet-Guilbert
- Université de Brest, Inserm, EFS, UMR 1078, GGB, F-29200 Brest, France; (B.S.); (D.G.B.)
- CHRU Brest, Service de Génétique, Laboratoire de Génétique Chromosomique, F-29200 Brest, France
- CHRU Brest, Centre de Ressources Biologiques, Site Cytogénétique, F-29200 Brest, France
| | - Benoît Soubise
- Université de Brest, Inserm, EFS, UMR 1078, GGB, F-29200 Brest, France; (B.S.); (D.G.B.)
| | - Delphine G. Bernard
- Université de Brest, Inserm, EFS, UMR 1078, GGB, F-29200 Brest, France; (B.S.); (D.G.B.)
- CHRU Brest, Service de Génétique, Laboratoire de Génétique Chromosomique, F-29200 Brest, France
- CHRU Brest, Centre de Ressources Biologiques, Site Cytogénétique, F-29200 Brest, France
| | - Marie-Bérengère Troadec
- Université de Brest, Inserm, EFS, UMR 1078, GGB, F-29200 Brest, France; (B.S.); (D.G.B.)
- CHRU Brest, Service de Génétique, Laboratoire de Génétique Chromosomique, F-29200 Brest, France
- CHRU Brest, Centre de Ressources Biologiques, Site Cytogénétique, F-29200 Brest, France
| |
Collapse
|
5
|
The role of RNA binding proteins in hepatocellular carcinoma. Adv Drug Deliv Rev 2022; 182:114114. [PMID: 35063534 DOI: 10.1016/j.addr.2022.114114] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 12/02/2021] [Accepted: 01/12/2022] [Indexed: 12/24/2022]
Abstract
Hepatocellular carcinoma (HCC) is one of the leading causes of overall cancer deaths worldwide with limited therapeutic options. Due to the heterogeneity of HCC pathogenesis, the molecular mechanisms underlying HCC development are not fully understood. Emerging evidence indicates that RNA-binding proteins (RBPs) play a vital role throughout hepatocarcinogenesis. Thus, a deeper understanding of how RBPs contribute to HCC progression will provide new tools for early diagnosis and prognosis of this devastating disease. In this review, we summarize the tumor suppressive and oncogenic roles of RBPs and their roles in hepatocarcinogenesis. The diagnostic and therapeutic potential of RBPs in HCC, including their limitations, are also discussed.
Collapse
|
6
|
Yan T, Heng Y, Wang W, Li J, Deng XW. SWELLMAP 2, a phyB-Interacting Splicing Factor, Negatively Regulates Seedling Photomorphogenesis in Arabidopsis. FRONTIERS IN PLANT SCIENCE 2022; 13:836519. [PMID: 35222493 PMCID: PMC8867171 DOI: 10.3389/fpls.2022.836519] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Accepted: 01/17/2022] [Indexed: 06/14/2023]
Abstract
Light-triggered transcriptome reprogramming is critical for promoting photomorphogenesis in Arabidopsis seedlings. Nonetheless, recent studies have shed light on the importance of alternative pre-mRNA splicing (AS) in photomorphogenesis. The splicing factors splicing factor for phytochrome signaling (SFPS) and reduced red-light responses in cry1cry2 background1 (RRC1) are involved in the phytochrome B (phyB) signaling pathway and promote photomorphogenesis by controlling pre-mRNA splicing of light- and clock-related genes. However, splicing factors that serve as repressors in phyB signaling pathway remain unreported. Here, we report that the splicing factor SWELLMAP 2 (SMP2) suppresses photomorphogenesis in the light. SMP2 physically interacts with phyB and colocalizes with phyB in photobodies after light exposure. Genetic analyses show that SMP2 antagonizes phyB signaling to promote hypocotyl elongation in the light. The homologs of SMP2 in yeast and human belong to second-step splicing factors required for proper selection of the 3' splice site (3'SS) of an intron. Notably, SMP2 reduces the abundance of the functional REVEILLE 8 a (RVE8a) form, probably by determining the 3'SS, and thereby inhibits RVE8-mediated transcriptional activation of clock genes containing evening elements (EE). Finally, SMP2-mediated reduction of functional RVE8 isoform promotes phytochrome interacting factor 4 (PIF4) expression to fine-tune hypocotyl elongation in the light. Taken together, our data unveil a phyB-interacting splicing factor that negatively regulates photomorphogenesis, providing additional information for further mechanistic investigations regarding phyB-controlled AS of light- and clock-related genes.
Collapse
Affiliation(s)
- Tingting Yan
- Harbin Institute of Technology, Harbin, China
- Key Laboratory of Molecular Design for Plant Cell Factory of Guangdong Higher Education Institutes, Institute of Plant and Food Sciences, Department of Biology, School of Life Sciences, Southern University of Science and Technology, Shenzhen, China
| | - Yueqin Heng
- Key Laboratory of Molecular Design for Plant Cell Factory of Guangdong Higher Education Institutes, Institute of Plant and Food Sciences, Department of Biology, School of Life Sciences, Southern University of Science and Technology, Shenzhen, China
| | - Wenwei Wang
- Key Laboratory of Molecular Design for Plant Cell Factory of Guangdong Higher Education Institutes, Institute of Plant and Food Sciences, Department of Biology, School of Life Sciences, Southern University of Science and Technology, Shenzhen, China
| | - Jian Li
- Key Laboratory of Molecular Design for Plant Cell Factory of Guangdong Higher Education Institutes, Institute of Plant and Food Sciences, Department of Biology, School of Life Sciences, Southern University of Science and Technology, Shenzhen, China
| | - Xing Wang Deng
- Key Laboratory of Molecular Design for Plant Cell Factory of Guangdong Higher Education Institutes, Institute of Plant and Food Sciences, Department of Biology, School of Life Sciences, Southern University of Science and Technology, Shenzhen, China
- State Key Laboratory of Protein and Plant Gene Research, School of Advanced Agricultural Sciences and School of Life Sciences, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, China
| |
Collapse
|
7
|
Gárate-Rascón M, Recalde M, Jimenez M, Elizalde M, Azkona M, Uriarte I, Latasa MU, Urtasun R, Bilbao I, Sangro B, Garcia-Ruiz C, Fernandez-Checa JC, Corrales FJ, Esquivel A, Pineda-Lucena A, Fernández-Barrena MG, Ávila MA, Arechederra M, Berasain C. Splicing Factor SLU7 Prevents Oxidative Stress-Mediated Hepatocyte Nuclear Factor 4α Degradation, Preserving Hepatic Differentiation and Protecting From Liver Damage. Hepatology 2021; 74:2791-2807. [PMID: 34170569 DOI: 10.1002/hep.32029] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Revised: 06/09/2021] [Accepted: 06/09/2021] [Indexed: 12/22/2022]
Abstract
BACKGROUND AND AIMS Hepatocellular dedifferentiation is emerging as an important determinant in liver disease progression. Preservation of mature hepatocyte identity relies on a set of key genes, predominantly the transcription factor hepatocyte nuclear factor 4α (HNF4α) but also splicing factors like SLU7. How these factors interact and become dysregulated and the impact of their impairment in driving liver disease are not fully understood. APPROACH AND RESULTS Expression of SLU7 and that of the adult and oncofetal isoforms of HNF4α, driven by its promoter 1 (P1) and P2, respectively, was studied in diseased human and mouse livers. Hepatic function and damage response were analyzed in wild-type and Slu7-haploinsufficient/heterozygous (Slu7+/- ) mice undergoing chronic (CCl4 ) and acute (acetaminophen) injury. SLU7 expression was restored in CCl4 -injured mice using SLU7-expressing adeno-associated viruses (AAV-SLU7). The hepatocellular SLU7 interactome was characterized by mass spectrometry. Reduced SLU7 expression in human and mouse diseased livers correlated with a switch in HNF4α P1 to P2 usage. This response was reproduced in Slu7+/- mice, which displayed increased sensitivity to chronic and acute liver injury, enhanced oxidative stress, and marked impairment of hepatic functions. AAV-SLU7 infection prevented liver injury and hepatocellular dedifferentiation. Mechanistically we demonstrate a unique role for SLU7 in the preservation of HNF4α1 protein stability through its capacity to protect the liver against oxidative stress. SLU7 is herein identified as a key component of the stress granule proteome, an essential part of the cell's antioxidant machinery. CONCLUSIONS Our results place SLU7 at the highest level of hepatocellular identity control, identifying SLU7 as a link between stress-protective mechanisms and liver differentiation. These findings emphasize the importance of the preservation of hepatic functions in the protection from liver injury.
Collapse
Affiliation(s)
| | - Miriam Recalde
- Hepatology Program, CIMA, University of Navarra, Pamplona, Spain
| | - Maddalen Jimenez
- Hepatology Program, CIMA, University of Navarra, Pamplona, Spain
| | - María Elizalde
- Hepatology Program, CIMA, University of Navarra, Pamplona, Spain
| | - María Azkona
- Hepatology Program, CIMA, University of Navarra, Pamplona, Spain
| | - Iker Uriarte
- Hepatology Program, CIMA, University of Navarra, Pamplona, Spain
- CIBERehd, Instituto de Salud Carlos III, Madrid, Spain
| | - M Uxue Latasa
- Hepatology Program, CIMA, University of Navarra, Pamplona, Spain
| | - Raquel Urtasun
- Hepatology Program, CIMA, University of Navarra, Pamplona, Spain
| | - Idoia Bilbao
- Hepatology Unit, Clínica Universidad de Navarra, Pamplona, Spain
| | - Bruno Sangro
- CIBERehd, Instituto de Salud Carlos III, Madrid, Spain
- Hepatology Unit, Clínica Universidad de Navarra, Pamplona, Spain
- Instituto de Investigaciones Sanitarias de Navarra IdiSNA, Pamplona, Spain
| | - Carmen Garcia-Ruiz
- CIBERehd, Instituto de Salud Carlos III, Madrid, Spain
- Cell Death and Proliferation, IIBB-CSIC, Barcelona, Spain
- Liver Unit, Hospital Clinic, IDIBAPS and CIBEREHD, Barcelona, Spain
| | - José C Fernandez-Checa
- CIBERehd, Instituto de Salud Carlos III, Madrid, Spain
- Cell Death and Proliferation, IIBB-CSIC, Barcelona, Spain
- Liver Unit, Hospital Clinic, IDIBAPS and CIBEREHD, Barcelona, Spain
| | - Fernando J Corrales
- CIBERehd, Instituto de Salud Carlos III, Madrid, Spain
- Functional Proteomics Laboratory, National Center for Biotechnology, Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Argitxu Esquivel
- Molecular Therapeutics Program, CIMA, University of Navarra, Pamplona, Spain
| | | | - Maite G Fernández-Barrena
- Hepatology Program, CIMA, University of Navarra, Pamplona, Spain
- CIBERehd, Instituto de Salud Carlos III, Madrid, Spain
- Instituto de Investigaciones Sanitarias de Navarra IdiSNA, Pamplona, Spain
| | - Matías A Ávila
- Hepatology Program, CIMA, University of Navarra, Pamplona, Spain
- CIBERehd, Instituto de Salud Carlos III, Madrid, Spain
- Instituto de Investigaciones Sanitarias de Navarra IdiSNA, Pamplona, Spain
| | - María Arechederra
- Hepatology Program, CIMA, University of Navarra, Pamplona, Spain
- Instituto de Investigaciones Sanitarias de Navarra IdiSNA, Pamplona, Spain
| | - Carmen Berasain
- Hepatology Program, CIMA, University of Navarra, Pamplona, Spain
- CIBERehd, Instituto de Salud Carlos III, Madrid, Spain
- Instituto de Investigaciones Sanitarias de Navarra IdiSNA, Pamplona, Spain
| |
Collapse
|
8
|
Farina AR, Cappabianca L, Sebastiano M, Zelli V, Guadagni S, Mackay AR. Hypoxia-induced alternative splicing: the 11th Hallmark of Cancer. J Exp Clin Cancer Res 2020; 39:110. [PMID: 32536347 PMCID: PMC7294618 DOI: 10.1186/s13046-020-01616-9] [Citation(s) in RCA: 74] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Accepted: 06/03/2020] [Indexed: 12/16/2022] Open
Abstract
Hypoxia-induced alternative splicing is a potent driving force in tumour pathogenesis and progression. In this review, we update currents concepts of hypoxia-induced alternative splicing and how it influences tumour biology. Following brief descriptions of tumour-associated hypoxia and the pre-mRNA splicing process, we review the many ways hypoxia regulates alternative splicing and how hypoxia-induced alternative splicing impacts each individual hallmark of cancer. Hypoxia-induced alternative splicing integrates chemical and cellular tumour microenvironments, underpins continuous adaptation of the tumour cellular microenvironment responsible for metastatic progression and plays clear roles in oncogene activation and autonomous tumour growth, tumor suppressor inactivation, tumour cell immortalization, angiogenesis, tumour cell evasion of programmed cell death and the anti-tumour immune response, a tumour-promoting inflammatory response, adaptive metabolic re-programming, epithelial to mesenchymal transition, invasion and genetic instability, all of which combine to promote metastatic disease. The impressive number of hypoxia-induced alternative spliced protein isoforms that characterize tumour progression, classifies hypoxia-induced alternative splicing as the 11th hallmark of cancer, and offers a fertile source of potential diagnostic/prognostic markers and therapeutic targets.
Collapse
Affiliation(s)
- Antonietta Rosella Farina
- Department of Applied Clinical and Biotechnological Sciences, University of L’Aquila, 67100 L’Aquila, Italy
| | - Lucia Cappabianca
- Department of Applied Clinical and Biotechnological Sciences, University of L’Aquila, 67100 L’Aquila, Italy
| | - Michela Sebastiano
- Department of Applied Clinical and Biotechnological Sciences, University of L’Aquila, 67100 L’Aquila, Italy
| | - Veronica Zelli
- Department of Applied Clinical and Biotechnological Sciences, University of L’Aquila, 67100 L’Aquila, Italy
| | - Stefano Guadagni
- Department of Applied Clinical and Biotechnological Sciences, University of L’Aquila, 67100 L’Aquila, Italy
| | - Andrew Reay Mackay
- Department of Applied Clinical and Biotechnological Sciences, University of L’Aquila, 67100 L’Aquila, Italy
| |
Collapse
|
9
|
Sun C. The SF3b complex: splicing and beyond. Cell Mol Life Sci 2020; 77:3583-3595. [PMID: 32140746 PMCID: PMC7452928 DOI: 10.1007/s00018-020-03493-z] [Citation(s) in RCA: 65] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Revised: 02/13/2020] [Accepted: 02/20/2020] [Indexed: 12/17/2022]
Abstract
The SF3b complex is an intrinsic component of the functional U2 small nuclear ribonucleoprotein (snRNP). As U2 snRNP enters nuclear pre-mRNA splicing, SF3b plays key roles in recognizing the branch point sequence (BPS) and facilitating spliceosome assembly and activation. Since the discovery of SF3b, substantial progress has been made in elucidating its molecular mechanism during splicing. In addition, numerous recent studies indicate that SF3b and its components are engaged in various molecular and cellular events that are beyond the canonical role in splicing. This review summarizes the current knowledge on the SF3b complex and highlights its multiple roles in splicing and beyond.
Collapse
Affiliation(s)
- Chengfu Sun
- Non-coding RNA and Drug Discovery Key Laboratory of Sichuan Province, Chengdu Medical College, Chengdu, 610500, China.
| |
Collapse
|
10
|
Wang J, Kainrad N, Shen H, Zhou Z, Rote P, Zhang Y, Nagy LE, Wu J, You M. Hepatic Knockdown of Splicing Regulator Slu7 Ameliorates Inflammation and Attenuates Liver Injury in Ethanol-Fed Mice. THE AMERICAN JOURNAL OF PATHOLOGY 2018; 188:1807-1819. [PMID: 29870742 DOI: 10.1016/j.ajpath.2018.05.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2018] [Revised: 04/16/2018] [Accepted: 05/03/2018] [Indexed: 12/11/2022]
Abstract
Aberrant precursor mRNA splicing plays a pivotal role in liver diseases. However, roles of splicing regulators in alcoholic liver disease are unknown. Herein, we investigated a splicing regulator, Slu7, in the development of alcoholic steatohepatitis. Adenovirus-mediated alteration of hepatic Slu7 expression in mice pair fed either with or without (as control) ethanol in their diet was used. Knockdown of hepatic Slu7 by adenovirus-Slu7shRNA treatment ameliorated inflammation and attenuated liver injury in mice after ethanol administration. Mechanistically, reducing liver Slu7 expression increased the expression of sirtuin 1 (SIRT1) full-length and repressed the splicing of SIRT1 into SIRT1-ΔExon8 isoform in ethanol-fed mice. Knockdown of hepatic Slu7 in the ethanol-fed mice also ameliorated splicing of lipin-1 and serine/arginine-rich splicing factor 3 (Srsf3). In concordance with ameliorated splicing of SIRT1, lipin-1, and Srsf3, knockdown of hepatic Slu7 inhibited the activity of NF-κB, normalized iron and zinc homeostasis, reduced oxidative stress, and attenuated liver damage in ethanol-fed mice. In addition, hepatic Slu7 was significantly elevated in patients with alcoholic steatohepatitis. Our present study illustrates a novel role of Slu7 in alcoholic liver injury and suggests that dysregulated Slu7 may contribute to the pathogenesis of human alcoholic steatohepatitis.
Collapse
Affiliation(s)
- Jiayou Wang
- Department of Pharmaceutical Sciences, College of Pharmacy, Northeast Ohio Medical University, Rootstown, Ohio; Department of Anatomy, School of Fundamental Medical Science, Guangzhou University of Chinese Medicine, Guangzhou, People's Republic of China
| | - Noah Kainrad
- Department of Pharmaceutical Sciences, College of Pharmacy, Northeast Ohio Medical University, Rootstown, Ohio
| | - Hong Shen
- Department of Pharmaceutical Sciences, College of Pharmacy, Northeast Ohio Medical University, Rootstown, Ohio; Department of Liver Diseases, Guangdong Hospital of Traditional Chinese Medicine in Zhuhai, Zhuhai, People's Republic of China
| | - Zhou Zhou
- Department of Pharmaceutical Sciences, College of Pharmacy, Northeast Ohio Medical University, Rootstown, Ohio
| | - Paula Rote
- Department of Integrative Medical Sciences, Northeast Ohio Medical University, Rootstown, Ohio
| | - Yanqiao Zhang
- Department of Integrative Medical Sciences, Northeast Ohio Medical University, Rootstown, Ohio
| | - Laura E Nagy
- Department of Pathobiology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio
| | - Jiashin Wu
- Department of Pharmaceutical Sciences, College of Pharmacy, Northeast Ohio Medical University, Rootstown, Ohio
| | - Min You
- Department of Pharmaceutical Sciences, College of Pharmacy, Northeast Ohio Medical University, Rootstown, Ohio.
| |
Collapse
|
11
|
Melangath G, Sen T, Kumar R, Bawa P, Srinivasan S, Vijayraghavan U. Functions for fission yeast splicing factors SpSlu7 and SpPrp18 in alternative splice-site choice and stress-specific regulated splicing. PLoS One 2017; 12:e0188159. [PMID: 29236736 PMCID: PMC5728500 DOI: 10.1371/journal.pone.0188159] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2017] [Accepted: 11/01/2017] [Indexed: 01/23/2023] Open
Abstract
Budding yeast spliceosomal factors ScSlu7 and ScPrp18 interact and mediate intron 3'ss choice during second step pre-mRNA splicing. The fission yeast genome with abundant multi-intronic transcripts, degenerate splice signals and SR proteins is an apt unicellular fungal model to deduce roles for core spliceosomal factors in alternative splice-site choice, intron retention and to study the cellular implications of regulated splicing. From our custom microarray data we deduce a stringent reproducible subset of S. pombe alternative events. We examined the role of factors SpSlu7 or SpPrp18 for these splice events and investigated the relationship to growth phase and stress. Wild-type log and stationary phase cells showed ats1+ exon 3 skipped and intron 3 retained transcripts. Interestingly the non-consensus 5'ss in ats1+ intron 3 caused SpSlu7 and SpPrp18 dependent intron retention. We validated the use of an alternative 5'ss in dtd1+ intron 1 and of an upstream alternative 3'ss in DUF3074 intron 1. The dtd1+ intron 1 non-canonical 5'ss yielded an alternative mRNA whose levels increased in stationary phase. Utilization of dtd1+ intron 1 sub-optimal 5' ss required functional SpPrp18 and SpSlu7 while compromise in SpSlu7 function alone hampered the selection of the DUF3074 intron 1 non canonical 3'ss. We analysed the relative abundance of these splice isoforms during mild thermal, oxidative and heavy metal stress and found stress-specific splice patterns for ats1+ and DUF3074 intron 1 some of which were SpSlu7 and SpPrp18 dependent. By studying ats1+ splice isoforms during compromised transcription elongation rates in wild-type, spslu7-2 and spprp18-5 mutant cells we found dynamic and intron context-specific effects in splice-site choice. Our work thus shows the combinatorial effects of splice site strength, core splicing factor functions and transcription elongation kinetics to dictate alternative splice patterns which in turn serve as an additional recourse of gene regulation in fission yeast.
Collapse
Affiliation(s)
- Geetha Melangath
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, Karnataka, India
| | - Titash Sen
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, Karnataka, India
| | - Rakesh Kumar
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, Karnataka, India
| | - Pushpinder Bawa
- Institute of Bioinformatics and Applied Biotechnology, Bangalore, Karnataka, India
| | - Subha Srinivasan
- Institute of Bioinformatics and Applied Biotechnology, Bangalore, Karnataka, India
| | - Usha Vijayraghavan
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, Karnataka, India
| |
Collapse
|
12
|
Giono LE, Nieto Moreno N, Cambindo Botto AE, Dujardin G, Muñoz MJ, Kornblihtt AR. The RNA Response to DNA Damage. J Mol Biol 2016; 428:2636-2651. [PMID: 26979557 DOI: 10.1016/j.jmb.2016.03.004] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2015] [Revised: 03/01/2016] [Accepted: 03/07/2016] [Indexed: 02/01/2023]
Abstract
Multicellular organisms must ensure genome integrity to prevent accumulation of mutations, cell death, and cancer. The DNA damage response (DDR) is a complex network that senses, signals, and executes multiple programs including DNA repair, cell cycle arrest, senescence, and apoptosis. This entails regulation of a variety of cellular processes: DNA replication and transcription, RNA processing, mRNA translation and turnover, and post-translational modification, degradation, and relocalization of proteins. Accumulated evidence over the past decades has shown that RNAs and RNA metabolism are both regulators and regulated actors of the DDR. This review aims to present a comprehensive overview of the current knowledge on the many interactions between the DNA damage and RNA fields.
Collapse
Affiliation(s)
- Luciana E Giono
- Instituto de Fisiología, Biología Molecular y Neurociencias (IFIBYNE-UBA-CONICET), Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pabellón 2, C1428EHA Buenos Aires, Argentina; Departamento de Fisiología, Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pabellón 2, C1428EHA Buenos Aires, Argentina
| | - Nicolás Nieto Moreno
- Instituto de Fisiología, Biología Molecular y Neurociencias (IFIBYNE-UBA-CONICET), Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pabellón 2, C1428EHA Buenos Aires, Argentina; Departamento de Fisiología, Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pabellón 2, C1428EHA Buenos Aires, Argentina
| | - Adrián E Cambindo Botto
- Instituto de Fisiología, Biología Molecular y Neurociencias (IFIBYNE-UBA-CONICET), Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pabellón 2, C1428EHA Buenos Aires, Argentina; Departamento de Fisiología, Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pabellón 2, C1428EHA Buenos Aires, Argentina
| | - Gwendal Dujardin
- Instituto de Fisiología, Biología Molecular y Neurociencias (IFIBYNE-UBA-CONICET), Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pabellón 2, C1428EHA Buenos Aires, Argentina; Departamento de Fisiología, Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pabellón 2, C1428EHA Buenos Aires, Argentina; Centre for Genomic Regulation, Dr. Aiguader 88, E-08003 Barcelona, Spain
| | - Manuel J Muñoz
- Instituto de Fisiología, Biología Molecular y Neurociencias (IFIBYNE-UBA-CONICET), Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pabellón 2, C1428EHA Buenos Aires, Argentina; Departamento de Fisiología, Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pabellón 2, C1428EHA Buenos Aires, Argentina
| | - Alberto R Kornblihtt
- Instituto de Fisiología, Biología Molecular y Neurociencias (IFIBYNE-UBA-CONICET), Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pabellón 2, C1428EHA Buenos Aires, Argentina; Departamento de Fisiología, Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pabellón 2, C1428EHA Buenos Aires, Argentina.
| |
Collapse
|
13
|
Elizalde M, Urtasun R, Azkona M, Latasa MU, Goñi S, García-Irigoyen O, Uriarte I, Segura V, Collantes M, Di Scala M, Lujambio A, Prieto J, Ávila MA, Berasain C. Splicing regulator SLU7 is essential for maintaining liver homeostasis. J Clin Invest 2014; 124:2909-20. [PMID: 24865429 DOI: 10.1172/jci74382] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2013] [Accepted: 03/28/2014] [Indexed: 12/13/2022] Open
Abstract
A precise equilibrium between cellular differentiation and proliferation is fundamental for tissue homeostasis. Maintaining this balance is particularly important for the liver, a highly differentiated organ with systemic metabolic functions that is endowed with unparalleled regenerative potential. Carcinogenesis in the liver develops as the result of hepatocellular de-differentiation and uncontrolled proliferation. Here, we identified SLU7, which encodes a pre-mRNA splicing regulator that is inhibited in hepatocarcinoma, as a pivotal gene for hepatocellular homeostasis. SLU7 knockdown in human liver cells and mouse liver resulted in profound changes in pre-mRNA splicing and gene expression, leading to impaired glucose and lipid metabolism, refractoriness to key metabolic hormones, and reversion to a fetal-like gene expression pattern. Additionally, loss of SLU7 also increased hepatocellular proliferation and induced a switch to a tumor-like glycolytic phenotype. Slu7 governed the splicing and/or expression of multiple genes essential for hepatocellular differentiation, including serine/arginine-rich splicing factor 3 (Srsf3) and hepatocyte nuclear factor 4α (Hnf4α), and was critical for cAMP-regulated gene transcription. Together, out data indicate that SLU7 is central regulator of hepatocyte identity and quiescence.
Collapse
|
14
|
Berasain C, Elizalde M, Urtasun R, Castillo J, García-Irigoyen O, Uriarte I, Latasa MU, Prieto J, Avila MA. Alterations in the expression and activity of pre-mRNA splicing factors in hepatocarcinogenesis. Hepat Oncol 2014; 1:241-252. [PMID: 30190958 DOI: 10.2217/hep.13.17] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Hepatocellular carcinoma (HCC) is a molecularly complex tumor that is resistant to standard and targeted therapies, and thus a deadly disease. In this context, the identification of key alterations driving HCC development is therefore essential. The implementation of next-generation sequencing techniques has underscored earlier realizations of the marked dysregulation of pre-mRNA splicing in HCC. Impairments in alternative splicing may lead to the expression of protumorigenic protein isoforms and to the generation of unstable mRNA species. Mechanistically, mutations in key nucleotides are responsible for many of these alterations in different types of tumors. However, changes in the expression of factors involved in the regulation of the splicing machinery are also important determinants in the derangement of pre-mRNA splicing. Here we discuss recent reports on the alteration of splicing factors in HCC, the pathological significance of these changes, and the identification of cell signaling pathways leading to the missplicing of genes in hepatocarcinogenesis.
Collapse
Affiliation(s)
- Carmen Berasain
- Division of Hepatology & Gene Therapy, Centro de Investigación Médica Aplicada (CIMA), Universidad de Navarra, CIMA, Avda, Pio XII, n55, 31008 Pamplona, Spain.,CIBERehd, Instituto de Salud Carlos III, Madrid, Spain.,Division of Hepatology & Gene Therapy, Centro de Investigación Médica Aplicada (CIMA), Universidad de Navarra, CIMA, Avda, Pio XII, n55, 31008 Pamplona, Spain.,CIBERehd, Instituto de Salud Carlos III, Madrid, Spain
| | - María Elizalde
- Division of Hepatology & Gene Therapy, Centro de Investigación Médica Aplicada (CIMA), Universidad de Navarra, CIMA, Avda, Pio XII, n55, 31008 Pamplona, Spain.,CIBERehd, Instituto de Salud Carlos III, Madrid, Spain.,Division of Hepatology & Gene Therapy, Centro de Investigación Médica Aplicada (CIMA), Universidad de Navarra, CIMA, Avda, Pio XII, n55, 31008 Pamplona, Spain.,CIBERehd, Instituto de Salud Carlos III, Madrid, Spain
| | - Raquel Urtasun
- Division of Hepatology & Gene Therapy, Centro de Investigación Médica Aplicada (CIMA), Universidad de Navarra, CIMA, Avda, Pio XII, n55, 31008 Pamplona, Spain.,CIBERehd, Instituto de Salud Carlos III, Madrid, Spain.,Division of Hepatology & Gene Therapy, Centro de Investigación Médica Aplicada (CIMA), Universidad de Navarra, CIMA, Avda, Pio XII, n55, 31008 Pamplona, Spain.,CIBERehd, Instituto de Salud Carlos III, Madrid, Spain
| | - Josefa Castillo
- Division of Hepatology & Gene Therapy, Centro de Investigación Médica Aplicada (CIMA), Universidad de Navarra, CIMA, Avda, Pio XII, n55, 31008 Pamplona, Spain.,Division of Hepatology & Gene Therapy, Centro de Investigación Médica Aplicada (CIMA), Universidad de Navarra, CIMA, Avda, Pio XII, n55, 31008 Pamplona, Spain
| | - Oihane García-Irigoyen
- Division of Hepatology & Gene Therapy, Centro de Investigación Médica Aplicada (CIMA), Universidad de Navarra, CIMA, Avda, Pio XII, n55, 31008 Pamplona, Spain.,CIBERehd, Instituto de Salud Carlos III, Madrid, Spain.,Division of Hepatology & Gene Therapy, Centro de Investigación Médica Aplicada (CIMA), Universidad de Navarra, CIMA, Avda, Pio XII, n55, 31008 Pamplona, Spain.,CIBERehd, Instituto de Salud Carlos III, Madrid, Spain
| | - Iker Uriarte
- Division of Hepatology & Gene Therapy, Centro de Investigación Médica Aplicada (CIMA), Universidad de Navarra, CIMA, Avda, Pio XII, n55, 31008 Pamplona, Spain.,CIBERehd, Instituto de Salud Carlos III, Madrid, Spain.,Division of Hepatology & Gene Therapy, Centro de Investigación Médica Aplicada (CIMA), Universidad de Navarra, CIMA, Avda, Pio XII, n55, 31008 Pamplona, Spain.,CIBERehd, Instituto de Salud Carlos III, Madrid, Spain
| | - Maria U Latasa
- Division of Hepatology & Gene Therapy, Centro de Investigación Médica Aplicada (CIMA), Universidad de Navarra, CIMA, Avda, Pio XII, n55, 31008 Pamplona, Spain.,CIBERehd, Instituto de Salud Carlos III, Madrid, Spain.,Division of Hepatology & Gene Therapy, Centro de Investigación Médica Aplicada (CIMA), Universidad de Navarra, CIMA, Avda, Pio XII, n55, 31008 Pamplona, Spain.,CIBERehd, Instituto de Salud Carlos III, Madrid, Spain
| | - Jesús Prieto
- Division of Hepatology & Gene Therapy, Centro de Investigación Médica Aplicada (CIMA), Universidad de Navarra, CIMA, Avda, Pio XII, n55, 31008 Pamplona, Spain.,CIBERehd, Instituto de Salud Carlos III, Madrid, Spain.,Division of Hepatology & Gene Therapy, Centro de Investigación Médica Aplicada (CIMA), Universidad de Navarra, CIMA, Avda, Pio XII, n55, 31008 Pamplona, Spain.,CIBERehd, Instituto de Salud Carlos III, Madrid, Spain
| | - Matías A Avila
- Division of Hepatology & Gene Therapy, Centro de Investigación Médica Aplicada (CIMA), Universidad de Navarra, CIMA, Avda, Pio XII, n55, 31008 Pamplona, Spain.,CIBERehd, Instituto de Salud Carlos III, Madrid, Spain.,Division of Hepatology & Gene Therapy, Centro de Investigación Médica Aplicada (CIMA), Universidad de Navarra, CIMA, Avda, Pio XII, n55, 31008 Pamplona, Spain.,CIBERehd, Instituto de Salud Carlos III, Madrid, Spain
| |
Collapse
|
15
|
On the origins of the androgen receptor low molecular weight species. Discov Oncol 2013; 4:259-69. [PMID: 23860689 DOI: 10.1007/s12672-013-0152-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/21/2013] [Accepted: 06/12/2013] [Indexed: 12/11/2022] Open
Abstract
Prostate cancer (CaP), a commonly diagnosed malignancy, is readily treated by androgen ablation. This treatment temporarily halts the disease, but castration-resistant neoplasms that are refractory to current therapies emerge. While these neoplasms are no longer dependent on physiological levels of androgens, they remain reliant on the expression of the androgen receptor (AR). There are multiple mechanisms by which CaP cells circumvent androgen ablation therapies. These include AR mutations that broaden ligand specificity, AR overexpression, AR activation by growth factors and cytokines, overexpression of AR co-activators, altered steroid metabolism, and a locus-wide histone transcriptional activation of some AR targets. This review focuses on a more recently described mechanism: the expression of low molecular weight AR species that are missing the ligand-binding domain and function independently of ligand to drive proliferation. The etiology, biological activity, unique features, predictive value, and therapeutic implication of these androgen receptor isoforms are discussed in depth.
Collapse
|
16
|
Splicing functions and global dependency on fission yeast slu7 reveal diversity in spliceosome assembly. Mol Cell Biol 2013; 33:3125-36. [PMID: 23754748 DOI: 10.1128/mcb.00007-13] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The multiple short introns in Schizosaccharomyces pombe genes with degenerate cis sequences and atypically positioned polypyrimidine tracts make an interesting model to investigate canonical and alternative roles for conserved splicing factors. Here we report functions and interactions of the S. pombe slu7(+) (spslu7(+)) gene product, known from Saccharomyces cerevisiae and human in vitro reactions to assemble into spliceosomes after the first catalytic reaction and to dictate 3' splice site choice during the second reaction. By using a missense mutant of this essential S. pombe factor, we detected a range of global splicing derangements that were validated in assays for the splicing status of diverse candidate introns. We ascribe widespread, intron-specific SpSlu7 functions and have deduced several features, including the branch nucleotide-to-3' splice site distance, intron length, and the impact of its A/U content at the 5' end on the intron's dependence on SpSlu7. The data imply dynamic substrate-splicing factor relationships in multiintron transcripts. Interestingly, the unexpected early splicing arrest in spslu7-2 revealed a role before catalysis. We detected a salt-stable association with U5 snRNP and observed genetic interactions with spprp1(+), a homolog of human U5-102k factor. These observations together point to an altered recruitment and dependence on SpSlu7, suggesting its role in facilitating transitions that promote catalysis, and highlight the diversity in spliceosome assembly.
Collapse
|
17
|
Montecucco A, Biamonti G. Pre-mRNA processing factors meet the DNA damage response. Front Genet 2013; 4:102. [PMID: 23761808 PMCID: PMC3674313 DOI: 10.3389/fgene.2013.00102] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2013] [Accepted: 05/20/2013] [Indexed: 12/04/2022] Open
Abstract
It is well-known that DNA-damaging agents induce genome instability, but only recently have we begun to appreciate that chromosomes are fragile per se and frequently subject to DNA breakage. DNA replication further magnifies such fragility, because it leads to accumulation of single-stranded DNA. Recent findings suggest that chromosome fragility is similarly increased during transcription. Transcripts produced by RNA polymerase II (RNAPII) are subject to multiple processing steps, including maturation of 5′ and 3′ ends and splicing, followed by transport to the cytoplasm. RNA maturation starts on nascent transcripts and is mediated by a number of diverse proteins and ribonucleoprotein particles some of which are recruited cotranscriptionally through interactions with the carboxy-terminal domain of RNAPII. This coupling is thought to maximize efficiency of pre-mRNA maturation and directly impacts the choice of alternative splice sites. Mounting evidence suggests that lack of coordination among different RNA maturation steps, by perturbing the interaction of nascent transcripts with the DNA template, has deleterious effects on genome stability. Thus, in the absence of proper surveillance mechanisms, transcription could be a major source of DNA damage in cancer. Recent high-throughput screenings in human cells and budding yeast have identified several factors implicated in RNA metabolism that are targets of DNA damage checkpoint kinases: ATM (ataxia telangiectasia mutated) and ATR (ATM-Rad3 related) (Tel1 and Mec1 in budding yeast, respectively). Moreover, inactivation of various RNA processing factors induces accumulation of γH2AX foci, an early sign of DNA damage. Thus, a complex network is emerging that links DNA repair and RNA metabolism. In this review we provide a comprehensive overview of the role played by pre-mRNA processing factors in the cell response to DNA damage and in the maintenance of genome stability.
Collapse
|
18
|
Kornblihtt AR, Schor IE, Alló M, Dujardin G, Petrillo E, Muñoz MJ. Alternative splicing: a pivotal step between eukaryotic transcription and translation. Nat Rev Mol Cell Biol 2013; 14:153-65. [PMID: 23385723 DOI: 10.1038/nrm3525] [Citation(s) in RCA: 605] [Impact Index Per Article: 50.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Alternative splicing was discovered simultaneously with splicing over three decades ago. Since then, an enormous body of evidence has demonstrated the prevalence of alternative splicing in multicellular eukaryotes, its key roles in determining tissue- and species-specific differentiation patterns, the multiple post- and co-transcriptional regulatory mechanisms that control it, and its causal role in hereditary disease and cancer. The emerging evidence places alternative splicing in a central position in the flow of eukaryotic genetic information, between transcription and translation, in that it can respond not only to various signalling pathways that target the splicing machinery but also to transcription factors and chromatin structure.
Collapse
Affiliation(s)
- Alberto R Kornblihtt
- Departamento de Fisiología, Biología Molecular y Celular e Instituto de Fisiología, Biología Molecular y Neurociencias, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, C1428EHA Buenos Aires, Argentina.
| | | | | | | | | | | |
Collapse
|
19
|
Blanco FJ, Bernabéu C. The Splicing Factor SRSF1 as a Marker for Endothelial Senescence. Front Physiol 2012; 3:54. [PMID: 22470345 PMCID: PMC3314196 DOI: 10.3389/fphys.2012.00054] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2011] [Accepted: 02/26/2012] [Indexed: 01/03/2023] Open
Abstract
Aging is the major risk factor per se for the development of cardiovascular diseases. The senescence of the endothelial cells (ECs) that line the lumen of blood vessels is the cellular basis for these age-dependent vascular pathologies, including atherosclerosis and hypertension. During their lifespan, ECs may reach a stage of senescence by two different pathways; a replicative one derived from their preprogrammed finite number of cell divisions; and one induced by stress stimuli. Also, certain physiological stimuli, such as transforming growth factor-β, are able to modulate cellular senescence. Currently, the cellular aging process is being widely studied to identify novel molecular markers whose changes correlate with senescence. This review focuses on the regulation of alternative splicing mediated by the serine-arginine splicing factor 1 (SRSF1, or ASF/SF2) during endothelial senescence, a process that is associated with a differential subcellular localization of SRSF1, which typically exhibits a scattered distribution throughout the cytoplasm. Based on its senescence-dependent involvement in alternative splicing, we postulate that SRSF1 is a key marker of EC senescence, regulating the expression of alternative isoforms of target genes such as endoglin (ENG), vascular endothelial growth factor A (VEGFA), tissue factor (T3), or lamin A (LMNA) that integrate in a common molecular senescence program.
Collapse
Affiliation(s)
- Francisco Javier Blanco
- Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas and Centro de Investigación Biomédica en Red de Enfermedades Raras Madrid, Spain
| | | |
Collapse
|
20
|
Pandey R, Mukerji M. From 'JUNK' to Just Unexplored Noncoding Knowledge: the case of transcribed Alus. Brief Funct Genomics 2011; 10:294-311. [DOI: 10.1093/bfgp/elr029] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
|
21
|
Paronetto M, Miñana B, Valcárcel J. The Ewing Sarcoma Protein Regulates DNA Damage-Induced Alternative Splicing. Mol Cell 2011; 43:353-68. [DOI: 10.1016/j.molcel.2011.05.035] [Citation(s) in RCA: 136] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2010] [Revised: 04/14/2011] [Accepted: 05/25/2011] [Indexed: 01/20/2023]
|
22
|
Functions of MDMX in the modulation of the p53-response. J Biomed Biotechnol 2011; 2011:876173. [PMID: 21541195 PMCID: PMC3085504 DOI: 10.1155/2011/876173] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2010] [Accepted: 01/21/2011] [Indexed: 12/21/2022] Open
Abstract
The MDM family proteins MDM2 and MDMX are two critical regulators of the p53 tumor suppressor protein. Expression of both proteins is necessary for allowing the embryonal development by keeping the activity of p53 in check. Upon stresses that need to activate p53 to perform its function as guardian of the genome, p53 has to be liberated from these two inhibitors. In this review, we will discuss the various mechanisms by which MDMX protein levels are downregulated upon various types of stress, including posttranslational modifications of the MDMX protein and the regulation of mdmx mRNA expression, including alternative splicing. In addition, the putative function(s) of the described MDMX splice variants, particularly in tumor development, will be discussed. Lastly, in contrast to common belief, we have recently shown the existence of a p53-MDMX feedback loop, which is important for dampening the p53-response at later phases after genotoxic stress.
Collapse
|
23
|
Ca2+-signaling, alternative splicing and endoplasmic reticulum stress responses. Neurochem Res 2011; 36:1198-211. [PMID: 21365449 DOI: 10.1007/s11064-011-0431-4] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/18/2011] [Indexed: 01/01/2023]
Abstract
Ca(2+)-signaling, alternative splicing, and stress responses by the endoplasmic reticulum are three important cellular activities which can be strongly interconnected to alter the expression of protein isoforms in a tissue dependent manner or during development depending on the environmental conditions. This integrated network of signaling pathways permits a high degree of versatility and adaptation to metabolic, developmental and stress processes. Defects in its regulation may lead to cellular malfunction.
Collapse
|
24
|
Janowicz A, Michalak M, Krebs J. Stress induced subcellular distribution of ALG-2, RBM22 and hSlu7. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2010; 1813:1045-9. [PMID: 21122810 DOI: 10.1016/j.bbamcr.2010.11.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2010] [Revised: 11/15/2010] [Accepted: 11/16/2010] [Indexed: 11/30/2022]
Abstract
ALG-2 is a highly conserved calcium binding protein in the cytoplasm which belongs to the family of penta-EF hand proteins. Recently, we showed that ALG-2 is interacting with RBM22, a highly conserved spliceosomal nuclear protein (Montaville et al. Biochim. Biophys. Acta 1763, 1335, 2006; Krebs, Biochim. Biophys. Acta 1793, 979, 2009). In NIH 3T3 cells expressing both proteins a significant amount of ALG-2mRFP is translocated to the nucleus due to the interaction with RBM22-EGFP. hSlu7, another spliceosomal nuclear protein, known to interact with RBM22 in yeast, has been shown to translocate to the cytoplasm under cellular stress conditions. Here we provide evidence that the 2 spliceosomal proteins differ significantly in their subcellular distributions under stress conditions, and that RBM22 enhances the cytoplasmic translocation of hSlu7 under stress, especially a stress induced by thapsigargin. On the other hand, in NIH 3T3 cells expressing RBM22-EGFP and ALG-2-mRFP, ALG-2 remains translocated into the nucleus under both stress conditions, i.e. heat shock or treatment with thapsigargin. We could further demonstrate that these stress conditions had a different influence on the splicing pattern of XBP-1, a marker for the unfolded protein response indicating that ER stress may play a role in stress-induced translocation of spliceosomal proteins. The article is part of a Special Issue entitled: 11th European Symposium on Calcium.
Collapse
Affiliation(s)
- Aleksandra Janowicz
- Department of Biochemistry, School of Molecular and Systems Biology, University of Alberta, Edmonton, Canada
| | | | | |
Collapse
|
25
|
Berasain C, Goñi S, Castillo J, Latasa MU, Prieto J, Ávila MA. Impairment of pre-mRNA splicing in liver disease: Mechanisms and consequences. World J Gastroenterol 2010; 16:3091-102. [PMID: 20593494 PMCID: PMC2896746 DOI: 10.3748/wjg.v16.i25.3091] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Pre-mRNA splicing is an essential step in the process of gene expression in eukaryotes and consists of the removal of introns and the linking of exons to generate mature mRNAs. This is a highly regulated mechanism that allows the alternative usage of exons, the retention of intronic sequences and the generation of exonic sequences of variable length. Most human genes undergo splicing events, and disruptions of this process have been associated with a variety of diseases, including cancer. Hepatocellular carcinoma (HCC) is a molecularly heterogeneous type of tumor that usually develops in a cirrhotic liver. Alterations in pre-mRNA splicing of some genes have been observed in liver cancer, and although still scarce, the available data suggest that splicing defects may have a role in hepatocarcinogenesis. Here we briefly review the general mechanisms that regulate pre-mRNA splicing, and discuss some examples that illustrate how this process is impaired in liver tumorigenesis, and may contribute to HCC development. We believe that a more thorough examination of pre-mRNA splicing is still needed to accurately draw the molecular portrait of liver cancer. This will surely contribute to a better understanding of the disease and to the development of new effective therapies.
Collapse
|
26
|
Sakashita E, Endo H. SR and SR-related proteins redistribute to segregated fibrillar components of nucleoli in a response to DNA damage. Nucleus 2010; 1:367-80. [PMID: 21327085 DOI: 10.4161/nucl.1.4.12683] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2010] [Revised: 06/15/2010] [Accepted: 06/16/2010] [Indexed: 11/19/2022] Open
Abstract
Pre-mRNA splicing factors are often redistributed to nucleoli in response to physiological conditions and cell stimuli. In telophase nuclei, serine-arginine rich (SR) proteins, which usually reside in nuclear speckles, localize transiently to active ribosomal DNA (rDNA) transcription sites called nucleolar organizing region-associated patches (NAPs). Here, we show that ultraviolet light and DNA damaging chemicals induce the redistribution of SR and SR-related proteins to areas around nucleolar fibrillar components in interphase nuclei that are similar to, but distinct from, NAPs, and these areas have been termed DNA damage-induced NAPs (d-NAPs). In vivo labeling of nascent RNA distinguished d-NAPs from NAPs in that d-NAPs were observed even after full rDNA transcriptional arrest as a result of DNA damage. Studies under a variety of conditions revealed that d-NAP formation requires both RNA polymerase II-dependent transcriptional arrest and nucleolar segregation, in particular, the disorganization of the granular nucleolar components. Despite the redistribution of SR proteins, splicing factor-enriched nuclear speckles were not disrupted because other nuclear speckle components, such as nuclear poly(A) RNA and the U5-116K protein, remained in DNA-damaged cells. These data suggest that the selective redistribution of splicing factors contributes to the regulation of specific genes via RNA metabolism. Finally, we demonstrate that a change in alternative splicing of apoptosis-related genes is coordinated with the occurrence of d-NAPs. Our results reveal a novel response to DNA damage that involves the dynamic redistribution of splicing factors to nucleoli.
Collapse
Affiliation(s)
- Eiji Sakashita
- Department of Biochemistry, Jichi Medical University School of Medicine, Tochigi, Japan.
| | | |
Collapse
|
27
|
Castillo J, Goñi S, Latasa MU, Perugorría MJ, Calvo A, Muntané J, Bioulac-Sage P, Balabaud C, Prieto J, Avila MA, Berasain C. Amphiregulin induces the alternative splicing of p73 into its oncogenic isoform DeltaEx2p73 in human hepatocellular tumors. Gastroenterology 2009; 137:1805-15.e1-4. [PMID: 19664633 DOI: 10.1053/j.gastro.2009.07.065] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/21/2009] [Revised: 06/19/2009] [Accepted: 07/30/2009] [Indexed: 01/17/2023]
Abstract
BACKGROUND & AIMS Inactivation of the product of the tumor suppressor gene TP73 does not usually occur by mutation but rather through expression of truncated isoforms that have dominant-negative effects on p73 and p53. The truncated oncogenic isoform DeltaEx2p73 is expressed in hepatocellular carcinomas (HCC) and is produced through the alternative splicing of p73 pre-messenger RNA (pre-mRNA); however, the underlying mechanisms regulating this process are unknown. METHODS We used human normal and diseased liver tissue samples, as well as human HCC cell lines, to examine the association between activation of epidermal growth factor receptor (EGFR) by its ligand amphiregulin (AR) and the alternative splicing of p73 pre-mRNA into the tumorigenic isoform DeltaEx2p73, via c-Jun N-terminal-kinase-1-mediated signaling. RESULTS DeltaEx2p73 was expressed in a subset of premalignant cirrhotic livers and in otherwise healthy livers that harbored a primary tumor, as well as in HCC tissues. DeltaEx2p73 expression was correlated with that of the EGFR ligand AR, which was previously shown to have a role in hepatocarcinogenesis. Autocrine activation of the EGFR by AR triggered c-Jun N-terminal kinase-1 activity and inhibited the expression of the splicing regulator Slu7, leading to the accumulation of DeltaEx2p73 transcripts in HCC cells. CONCLUSIONS This study provided a mechanism for the generation of protumorigenic DeltaEx2p73 during liver tumorigenesis, via activation of EGFR signaling by AR and c-Jun N-terminal kinase-1 activity, leading to inhibition of the splicing regulator Slu7.
Collapse
Affiliation(s)
- Josefa Castillo
- Division of Hepatology and Gene Therapy, CIMA-University of Navarra, Pamplona, Spain
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
28
|
Singh RK, Tapia-Santos A, Bebee TW, Chandler DS. Conserved sequences in the final intron of MDM2 are essential for the regulation of alternative splicing of MDM2 in response to stress. Exp Cell Res 2009; 315:3419-32. [PMID: 19631207 DOI: 10.1016/j.yexcr.2009.07.017] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2009] [Revised: 07/12/2009] [Accepted: 07/15/2009] [Indexed: 01/10/2023]
Abstract
Alternative splicing plays a fundamental role in generating proteome diversity and is critical in regulation of eukaryotic gene expression. It is estimated that 50% of disease-causing mutations alter splicing efficiency and/or patterns of splicing. An alternatively spliced form of murine double-minute 2, MDM2-ALT1, is associated with pediatric rhabdomyosarcoma (RMS) at high frequency in primary human tumors and RMS cell lines. We have identified that this isoform can be induced in response to specific types of stress (UV and cisplatin). However, the mechanism of alternative splicing of MDM2 in human cancer is unknown. Using UV and cisplatin to model alternative splicing of the MDM2 gene, we have developed a damage-inducible in vitro splicing system. This system employs an MDM2 minigene that mimics the damage-induced alternative splicing observed in vivo. Using this in vitro splicing system, we have shown that conserved intronic sequences in intron 11 of MDM2 are required for normal splicing. Furthermore, we showed that these intronic elements are also required for the regulated damage-induced alternative splicing of MDM2. The use of this novel damage-inducible system will allow for the systematic identification of regulatory elements and factors involved in the splicing regulation of the MDM2 gene in response to stress. This study has implications for identification of novel intervention points for development of future therapeutics for rhabdomyosarcoma.
Collapse
Affiliation(s)
- Ravi K Singh
- The Center for Childhood Cancer, The Research Institute at Nationwide Children's Hospital, Department of Pediatrics, The Ohio State University, Columbus, Ohio 43205, USA
| | | | | | | |
Collapse
|
29
|
Muñoz MJ, Pérez Santangelo MS, Paronetto MP, de la Mata M, Pelisch F, Boireau S, Glover-Cutter K, Ben-Dov C, Blaustein M, Lozano JJ, Bird G, Bentley D, Bertrand E, Kornblihtt AR. DNA damage regulates alternative splicing through inhibition of RNA polymerase II elongation. Cell 2009; 137:708-20. [PMID: 19450518 DOI: 10.1016/j.cell.2009.03.010] [Citation(s) in RCA: 243] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2008] [Revised: 01/22/2009] [Accepted: 03/02/2009] [Indexed: 10/20/2022]
Abstract
DNA damage induces apoptosis and many apoptotic genes are regulated via alternative splicing (AS), but little is known about the control mechanisms. Here we show that ultraviolet irradiation (UV) affects cotranscriptional AS in a p53-independent way, through the hyperphosphorylation of RNA polymerase II carboxy-terminal domain (CTD) and a subsequent inhibition of transcriptional elongation, estimated in vivo and in real time. Phosphomimetic CTD mutants not only display lower elongation but also duplicate the UV effect on AS. Consistently, nonphosphorylatable mutants prevent the UV effect. Apoptosis promoted by UV in cells lacking p53 is prevented when the change in AS of the apoptotic gene bcl-x is reverted, confirming the relevance of this mechanism. Splicing-sensitive microarrays revealed a significant overlap of the subsets of genes that have changed AS with UV and those that have reduced expression, suggesting that transcriptional coupling to AS is a key feature of the DNA-damage response.
Collapse
Affiliation(s)
- Manuel J Muñoz
- Laboratorio de Fisiología y Biología Molecular, Departamento de Fisiología, Biología Molecular y Celular, IFIBYNE-CONICET, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Argentina
| | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
30
|
Biamonti G, Caceres JF. Cellular stress and RNA splicing. Trends Biochem Sci 2009; 34:146-53. [PMID: 19208481 DOI: 10.1016/j.tibs.2008.11.004] [Citation(s) in RCA: 143] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2008] [Revised: 11/03/2008] [Accepted: 11/04/2008] [Indexed: 01/02/2023]
Abstract
In response to physical and chemical stresses that affect protein folding and, thus, the execution of normal metabolic processes, cells activate gene-expression strategies aimed at increasing their chance of survival. One target of several stressing agents is pre-mRNA splicing, which is inhibited upon heat shock. Recently, the molecular basis of this splicing inhibition has begun to emerge. Interestingly, different mechanisms seem to be in place to block constitutive pre-mRNA splicing and to affect alternative splicing regulation. This could be important to modulate gene expression during recovery from stress. Thus, pre-mRNA splicing emerges as a central mechanism to integrate cellular and metabolic stresses into gene-expression profiles.
Collapse
Affiliation(s)
- Giuseppe Biamonti
- Istituto di Genetica Molecolare-Consiglio Nazionale delle Ricerche Via Abbiategrasso 207, 27100 Pavia, Italy.
| | | |
Collapse
|
31
|
Nicholls CD, Beattie TL. Multiple factors influence the normal and UV-inducible alternative splicing of PIG3. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2008; 1779:838-49. [DOI: 10.1016/j.bbagrm.2008.08.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2008] [Revised: 08/15/2008] [Accepted: 08/20/2008] [Indexed: 10/21/2022]
|
32
|
Nakamori T, Fujimori A, Kinoshita K, Ban-Nai T, Kubota Y, Yoshida S. Application of HiCEP to screening of radiation stress-responsive genes in the soil microarthropod Folsomia candida (Collembola). ENVIRONMENTAL SCIENCE & TECHNOLOGY 2008; 42:6997-7002. [PMID: 18853822 DOI: 10.1021/es801128q] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
The field of ecotoxicogenomics has received increasing attention for its potential to provide insight into pressing ecological issues. However, its applications are limited due to a lack of genetic sequence information for organisms used in ecotoxicological studies. We used high-coverage expression profiling (HiCEP), a method that requires no prior sequence knowledge, to examine stress-responsive genes and their dose dependence in the springtail Folsomia candida using gamma radiation as the stressor. Radiation-responsive genes and their dose dependency were detected at effective doses for reproduction, and 16 up-regulated transcript-derived fragments (TDFs) were sequenced. Quantitative PCR analysis also found that most of the TDFs were up-regulated. The sequences of the TDFs showed resemblance to known genes, such as glutathione S-transferase and poly(ADP-ribose) polymerase, but most showed no similarity to any genes in the gene databases. These results suggest that HiCEP is effective for discovering differently expressed genes and their dose dependence, even in organisms for which few sequence data are available. The limited length of the TDFs, however, may impede functional annotation of the genes. In conclusion, HiCEP is useful for ecotoxicogenomic studies in which various organisms with few available genomic resources are involved.
Collapse
Affiliation(s)
- Taizo Nakamori
- Environmental Radiation Effects Research Group, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan.
| | | | | | | | | | | |
Collapse
|
33
|
Abstract
A substantial fraction (approximately 30%) of plant genes is alternatively spliced, but how alternative splicing is regulated remains unknown. Many plant genes undergo alternative splicing in response to a variety of stresses. Large-scale computational analyses and experimental approaches focused on select genes are beginning to reveal that alternative splicing constitutes an integral part of gene regulation in stress responses. Based on the studies discussed in this chapter, it appears that alternative splicing generates transcriptome/proteome complexity that is likely to be important for stress adaptation. However, the signaling pathways that relay stress conditions to splicing machinery and if and how the alternative spliced products confer adaptive advantages to plants are poorly understood.
Collapse
|
34
|
Takai K, Sakamoto S, Sakai T, Yasunaga JI, Komatsu K, Matsuoka M. A potential link between alternative splicing of the NBS1 gene and DNA damage/environmental stress. Radiat Res 2008; 170:33-40. [PMID: 18582154 DOI: 10.1667/rr1191.1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2007] [Accepted: 03/19/2008] [Indexed: 11/03/2022]
Abstract
NBS1 forms a multimetric complex with MRE11/RAD50, which acts as the sensor of DNA double-strand breaks (DSBs). The mechanisms controlling the expression of NBS1 remain largely unknown. Here we show that NBS1 is transcribed as both a wild-type and an alternatively spliced form exhibiting a premature stop codon in an alternative 50-bp exon in intron 2. Although the wild-type transcript predominates in most tissues, the spliced transcript is abundant in resting peripheral blood mononuclear cells (PBMCs). Levels of the spliced form of NBS1 decreased rapidly after irradiation as levels of the wild-type NBS1 transcript increased, resulting in increased levels of NBS1 protein. Both mitogenic stimulation and methyl methanesulfonate treatment also altered the splicing pattern of NBS1. Resting PBMCs, which predominantly express spliced NBS1, were more susceptible to radiation than mitogen-stimulated cells, which showed predominant expression of the wild-type transcript. Since the alternatively spliced NBS1 gene likely did not produce protein, this alternative splicing seems to be associated with the control of NBS1 protein. Thus alternative splicing of the NBS1 gene may be associated with the regulation of NBS1 in response to DSBs, DNA alkylation damage, and mitogenic response.
Collapse
Affiliation(s)
- Ken Takai
- Laboratory of Virus Control, Institute for Virus Research, Kyoto University, 53 Shogoin Kawara-cho, Sakyo-ku, Kyoto 606-8507, Japan
| | | | | | | | | | | |
Collapse
|
35
|
Cammas A, Lewis SM, Vagner S, Holcik M. Post-transcriptional control of gene expression through subcellular relocalization of mRNA binding proteins. Biochem Pharmacol 2008; 76:1395-403. [PMID: 18582437 DOI: 10.1016/j.bcp.2008.05.022] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2008] [Revised: 04/28/2008] [Accepted: 05/16/2008] [Indexed: 11/15/2022]
Abstract
Eukaryotic cells have developed multiple mechanisms to respond to different physiological cues, such as cellular stress, which allow the cells to adapt themselves to their new environment. The regulation of post-transcriptional gene expression is an important component of the cellular stress response and is mediated by mRNA binding proteins (mRBPs). Recently, several studies have shown that regulated subcellular localization of mRBPs upon diverse stimuli (such as cellular stress) provides an additional level of regulation for gene expression.
Collapse
|
36
|
Bortfeldt R, Schindler S, Szafranski K, Schuster S, Holste D. Comparative analysis of sequence features involved in the recognition of tandem splice sites. BMC Genomics 2008; 9:202. [PMID: 18447903 PMCID: PMC2423196 DOI: 10.1186/1471-2164-9-202] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2008] [Accepted: 04/30/2008] [Indexed: 01/05/2023] Open
Abstract
Background The splicing of pre-mRNAs is conspicuously often variable and produces multiple alternatively spliced (AS) isoforms that encode different messages from one gene locus. Computational studies uncovered a class of highly similar isoforms, which were related to tandem 5'-splice sites (5'ss) and 3'-splice sites (3'ss), yet with very sparse anecdotal evidence in experimental studies. To compare the types and levels of alternative tandem splice site exons occurring in different human organ systems and cell types, and to study known sequence features involved in the recognition and distinction of neighboring splice sites, we performed large-scale, stringent alignments of cDNA sequences and ESTs to the human and mouse genomes, followed by experimental validation. Results We analyzed alternative 5'ss exons (A5Es) and alternative 3'ss exons (A3Es), derived from transcript sequences that were aligned to assembled genome sequences to infer patterns of AS occurring in several thousands of genes. Comparing the levels of overlapping (tandem) and non-overlapping (competitive) A5Es and A3Es, a clear preference of isoforms was seen for tandem acceptors and donors, with four nucleotides and three to six nucleotides long exon extensions, respectively. A subset of inferred A5E tandem exons was selected and experimentally validated. With the focus on A5Es, we investigated their transcript coverage, sequence conservation and base-paring to U1 snRNA, proximal and distal splice site classification, candidate motifs for cis-regulatory activity, and compared A5Es with A3Es, constitutive and pseudo-exons, in H. sapiens and M. musculus. The results reveal a small but authentic enriched set of tandem splice site preference, with specific distances between proximal and distal 5'ss (3'ss), which showed a marked dichotomy between the levels of in- and out-of-frame splicing for A5Es and A3Es, respectively, identified a number of candidate NMD targets, and allowed a rough estimation of a number of undetected tandem donors based on splice site information. Conclusion This comparative study distinguishes tandem 5'ss and 3'ss, with three to six nucleotides long extensions, as having unusually high proportions of AS, experimentally validates tandem donors in a panel of different human tissues, highlights the dichotomy in the types of AS occurring at tandem splice sites, and elucidates that human alternative exons spliced at overlapping 5'ss posses features of typical splice variants that could well be beneficial for the cell.
Collapse
Affiliation(s)
- Ralf Bortfeldt
- Department of Bioinformatics, Friedrich-Schiller University, Ernst-Abbe-Platz 2, D-07743 Jena, Germany.
| | | | | | | | | |
Collapse
|
37
|
Alberstein M, Amit M, Vaknin K, O'Donnell A, Farhy C, Lerenthal Y, Shomron N, Shaham O, Sharrocks AD, Ashery-Padan R, Ast G. Regulation of transcription of the RNA splicing factor hSlu7 by Elk-1 and Sp1 affects alternative splicing. RNA (NEW YORK, N.Y.) 2007; 13:1988-99. [PMID: 17804646 PMCID: PMC2040095 DOI: 10.1261/rna.492907] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Alternative splicing plays a major role in transcriptome diversity and plasticity, but it is largely unknown how tissue-specific and embryogenesis-specific alternative splicing is regulated. The highly conserved splicing factor Slu7 is involved in 3' splice site selection and also regulates alternative splicing. We show that Slu7 has a unique spatial pattern of expression among human and mouse embryonic and adult tissues. We identified several functional Ets binding sites and GC-boxes in the human Slu7 (hSlu7) promoter region. The Ets and GC-box binding transcription factors, Elk-1 and Sp1, respectively, exerted opposite effects on hSlu7 transcription: Sp1 protein enhances and Elk-1 protein represses transcription in a dose-dependent manner. Sp1 protein bound to the hSlu7 promoter in vivo, and depletion of Sp1 by RNA interference (RNAi) repressed hSlu7 expression. Elk-1 protein bound to the hSlu7 promoter in vivo, and depletion of Elk-1 by RNAi caused an increase in the endogenous level of hSlu7 mRNA. Further, depletion of either Sp1 or Elk-1 affected alternative splicing. Our results provide indications of a complex transcription regulation mechanism that controls the spatial and temporal expression of Slu7, presumably allowing regulation of tissue-specific alternative splicing events.
Collapse
Affiliation(s)
- Moti Alberstein
- Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine, Tel-Aviv University, Tel Aviv, Israel
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
38
|
Qin W, Doucet D, Tyshenko MG, Walker VK. Transcription of antifreeze protein genes in Choristoneura fumiferana. INSECT MOLECULAR BIOLOGY 2007; 16:423-34. [PMID: 17651234 DOI: 10.1111/j.1365-2583.2007.00743.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Antifreeze proteins (AFPs) are encoded by approximately 17 genes in the spruce budworm, Choristoneura fumiferana. Northern analysis using 6 different cDNA probes showed isoform-specific patterns that varied during development. Transcripts for the majority of isoforms were most abundant in the second instar overwintering stage, but some were also detected in first instar and even in egg stages. In situ hybridization using riboprobes corresponding to two 9 kDa protein isoforms showed differential AFP expression even in second instars; CfAFP10 RNA was detected in all tissues, but CfAFP337 RNA distribution was more limited. Two genomic regions encoding three AFP genes have been isolated. Presumptive regulatory regions conferred transcriptional activity when placed upstream of a luciferase reporter sequence and transfected into a C. fumiferana cell line. The CfAFP2.26 core promoter is an 87 bp sequence containing a TATA box, whereas the CfAFP2.7 core promoter is a 76 bp sequence with both a TATA box and CAAT box, which directed higher reporter activities when tested in vitro. Reporter activity was not enhanced with five different hormones, although lower activities were observed with all intron-containing constructs. AFP message half-life, as assessed using reporter assays, was not appreciably influenced by isoform-specific-3'UTRs. These studies successfully demonstrate the temporal and spatial diversity of AFP expression encoded by this small gene family, and underscore the complexity of their regulation.
Collapse
Affiliation(s)
- W Qin
- Department of Biology, Queen's University, Kingston, Ontario, Canada
| | | | | | | |
Collapse
|
39
|
Abstract
AbstractAlternative splicing is an important cellular mechanism that increases the diversity of gene products. The study of alternatively spliced genes reported so far in plants is far less documented than that in mammals, but considerable results have been reported, showing the role of these genes in regulating mechanisms, influencing factors, and specificities and function of alternative splicing in plants. This review summarizes briefly the major progress made on alternative splicing in plants.
Collapse
|
40
|
Coyle DE. Spinal cord transcriptional profile analysis reveals protein trafficking and RNA processing as prominent processes regulated by tactile allodynia. Neuroscience 2007; 144:144-56. [PMID: 17069981 DOI: 10.1016/j.neuroscience.2006.08.081] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2006] [Revised: 08/14/2006] [Accepted: 08/30/2006] [Indexed: 11/29/2022]
Abstract
Since partial peripheral injury does not necessarily lead to the development of neuropathic pain it is possible that a set of genes is directly regulated by the development of neuropathic pain independent of the genes regulated by nerve injury. This study identifies the genes expressed within the spinal cord that are uniquely regulated by tactile allodynia in rats. Using subtractive methods, genes regulated by allodynia were differentiated from those of nerve injury. Gene ontology analysis identified that allodynic genes are involved in a variety of processes including myelination, actin cytoskeleton reorganization, dephosphorylation, phosphorylation, response to stress, as well as protein trafficking and RNA processing. The processes of protein trafficking and RNA processing were found to be as statistically significant as other processes that have been associated with neuropathic pain development such as response to stress, phosphorylation, and cell migration. Trafficking and transcription are linked and undergo activity dependent regulation which results in both rapid and gradual synaptic changes (plasticity). The data presented here greatly expand the list of genes regulated by the development of tactile allodynia and reveal protein trafficking and RNA processing as prominent biological processes that may be involved in synaptic plasticity changes within the spinal cord in response to allodynia.
Collapse
Affiliation(s)
- D E Coyle
- Department of Anesthesiology, University of Cincinnati, 231 Albert Sabin Way, PO Box 670531, Cincinnati, OH 45267-0531, USA.
| |
Collapse
|
41
|
Fiol DF, Mak SK, Kültz D. Specific TSC22 domain transcripts are hypertonically induced and alternatively spliced to protect mouse kidney cells during osmotic stress. FEBS J 2007; 274:109-24. [PMID: 17147695 DOI: 10.1111/j.1742-4658.2006.05569.x] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We recently cloned a novel osmotic stress transcription factor 1 (OSTF1) from gills of euryhaline tilapia (Oreochromis mossambicus) and demonstrated that acute hyperosmotic stress transiently increases OSTF1 mRNA and protein abundance [Fiol DF, Kültz D (2005) Proc Natl Acad Sci USA102, 927-932]. In this study, a genome-wide search was conducted to identify nine distinct mouse transforming growth factor (TGF)-beta-stimulated clone 22 domain (TSC22D) transcripts, including glucocorticoid-induced leucine zipper (GILZ), that are orthologs of OSTF1. These nine TSC22D transcripts are encoded at four loci on chromosomes 14 (TSC22D1, two splice variants), 3 (TSC22D2, four splice variants), X (TSC22D3, two splice variants), and 5 (TSC22D4). All nine mouse TSC22D transcripts are expressed in renal cortex, medulla and papilla, and in the mIMCD3 cell line. The two TSC22D3 transcripts (including GILZ) are upregulated by aldosterone but not by hyperosmolality in mIMCD3 cells. In contrast, TSC22D4 is stably upregulated by hyperosmolality in mIMCD3 cells and increased in renal papilla compared with cortex. Moreover, all four TSC22D2 transcripts are transiently upregulated by hyperosmolality and resemble tilapia OSTF1 in this regard. All TSC22D2 transcripts depend on hypertonicity as the signal for their upregulation and are unresponsive to increases in cell-permeable osmolytes. mRNA stabilization is the mechanism for TSC22D2 upregulation by hyperosmolality. Overexpression of TSC22D2-4 in mIMCD3 cells confers protection towards osmotic stress, as evidenced by a 2.7-fold increase in cell survival after 3 days at 600 mOsmol x kg(-1). Based on variable responsiveness to aldosterone and hyperosmolality in kidney cells we conclude that mouse TSC22D genes have diverse physiological functions. TSC22D2 and TSC22D4 are involved in adaptation of renal cells to hypertonicity suggesting that they represent important elements of osmosensory signal transduction in mouse kidney cells.
Collapse
Affiliation(s)
- Diego F Fiol
- Physiological Genomics Group, Department of Animal Science, University of California, Davis, CA 95616, USA
| | | | | |
Collapse
|
42
|
Nuclear organization and splicing control. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2007; 623:1-13. [PMID: 18380337 DOI: 10.1007/978-0-387-77374-2_1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Although major splicing regulatory mechanisms rely on the presence of cis-acting sequence elements in the precursor messenger RNA (pre-mRNA) to which specific protein and factors bind, splice choices are also influenced by transcription kinetics, promoter-dependent loading of RNA-binding proteins and nucleo-cytoplasmic distribution of splicing regulators. Within the highly crowded eukaryotic nucleus, molecular machines required for gene expression create specialized microenvironments that favor some interactions while repressing others. Genes located far apart in a chromosome or even in different chromosomes come together in the nucleus for coordinated transcription and splicing. Emerging tools to dissect gene expression pathways in living cells promise to provide more detailed insight as to how spatial confinement contributes to splicing control.
Collapse
|
43
|
Guil S, Long JC, Cáceres JF. hnRNP A1 relocalization to the stress granules reflects a role in the stress response. Mol Cell Biol 2006; 26:5744-58. [PMID: 16847328 PMCID: PMC1592774 DOI: 10.1128/mcb.00224-06] [Citation(s) in RCA: 256] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2006] [Revised: 03/01/2006] [Accepted: 05/09/2006] [Indexed: 02/07/2023] Open
Abstract
hnRNP A1 is a nucleocytoplasmic shuttling protein that is involved in many aspects of mRNA metabolism. We have previously shown that activation of the p38 stress-signaling pathway in mammalian cells results in both hyperphosphorylation and cytoplasmic accumulation of hnRNP A1, affecting alternative splicing regulation in vivo. Here we show that the stress-induced cytoplasmic accumulation of hnRNP A1 occurs in discrete phase-dense particles, the cytoplasmic stress granules (SGs). Interestingly, mRNA-binding activity is required for both phosphorylation of hnRNP A1 and localization to SGs. We also show that these effects are mediated by the Mnk1/2 protein kinases that act downstream of p38. Finally, depletion of hnRNP A1 affects the recovery of cells from stress, suggesting a physiologically significant role for hnRNP A1 in the stress response. Our data are consistent with a model whereby hnRNP A1 recruitment to SGs involves Mnk1/2-dependent phosphorylation of mRNA-bound hnRNP A1.
Collapse
Affiliation(s)
- Sonia Guil
- Medical Research Council Human Genetics Unit, Western General Hospital, Edinburgh, Scotland, United Kingdom
| | | | | |
Collapse
|
44
|
Scholzová E, Malík R, Sevcík J, Kleibl Z. RNA regulation and cancer development. Cancer Lett 2006; 246:12-23. [PMID: 16675105 DOI: 10.1016/j.canlet.2006.03.021] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2006] [Revised: 03/20/2006] [Accepted: 03/24/2006] [Indexed: 12/23/2022]
Abstract
Cancer is viewed as a genetic disease. According to the currently accepted model of carcinogenesis, several consequential mutations in oncogenes or tumor suppressor genes are necessary for cancer development. In this model, mutated DNA sequence is transcribed to mRNA that is finally translated into functionally aberrant protein. mRNA is viewed solely as an intermediate between DNA (with 'coding' potential) and protein (with 'executive' function). However, recent findings suggest that (m)RNA is actively regulated by a variety of processes including nonsense-mediated decay, alternative splicing, RNA editing or RNA interference. Moreover, RNA molecules can regulate a variety of cellular functions through interactions with RNA, DNA as well as protein molecules. Although, the precise contribution of RNA molecules by themselves and RNA-regulated processes on cancer development is currently unknown, recent data suggest their important role in carcinogenesis. Here, we summarize recent knowledge on RNA-related processes and discuss their potential role in cancer development.
Collapse
Affiliation(s)
- Eva Scholzová
- First Medical Faculty, Institute of Biochemistry and Experimental Oncology, Charles University, U Nemocnice 5, 128 53 Prague 2, Czech Republic.
| | | | | | | |
Collapse
|
45
|
Ben-Ari S, Toiber D, Sas AS, Soreq H, Ben-Shaul Y. Modulated splicing-associated gene expression in P19 cells expressing distinct acetylcholinesterase splice variants. J Neurochem 2006; 97 Suppl 1:24-34. [PMID: 16635247 DOI: 10.1111/j.1471-4159.2006.03725.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Alternative splicing configurations and acetylcholinesterase (AChE) gene expression are both modified in neurons under stress. However, it is unclear if these phenomena are functionally interrelated. Using a home-made spotted microarray focused on splicing-associated transcripts, we tested the effects of excess 3' splice variants of human AChE on splicing-related gene expression in semi-differentiated neuronal P19 cells. Of the tested transcripts, 17.3% and 20.2% showed modified expression levels (log2 of the ratio<-0.3 or>0.3) in transfected P19 cells overexpressing the stress-inducible AChE-R variant or the synaptic AChE-S protein, respectively. Multiple transcripts encoding serine-arginine rich (SR) and SR-related splicing regulators were suppressed in cells expressing either of these variants, whereas the gene groups including splicing-related helicases and transcripts involved in apoptosis displayed variant-specific changes. Our findings are compatible with the assumption that both neuronal overexpression and alternative splicing of pre-AChE mRNA may be causally involved in initiating global changes in neuronal alternative splicing, causing subsequent modifications in the expression patterns of numerous target genes.
Collapse
Affiliation(s)
- Shani Ben-Ari
- Department of Biological Chemistry and Israel Center for Neuronal Computation, The Hebrew University of Jerusalem, Jerusalem, Israel
| | | | | | | | | |
Collapse
|
46
|
Okumura M, Kondo S, Ogata M, Kanemoto S, Murakami T, Yanagida K, Saito A, Imaizumi K. Candidates for tumor-specific alternative splicing. Biochem Biophys Res Commun 2005; 334:23-9. [PMID: 16018876 DOI: 10.1016/j.bbrc.2005.06.057] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2005] [Accepted: 06/09/2005] [Indexed: 11/23/2022]
Abstract
Gene expression can be regulated not only by transcription and post-transcriptional modifications, but also by splicing regulation. Recent genome-wide analyses have indicated that up to 70% of human genes may have alternatively spliced forms, suggesting that splicing regulation affects a wide range of gene expression. Tumor tissues show significantly altered protein expressions, and this is also thought to be affected by alternative splicing. Although some alternative splicing events have been reported to be cancer specific and others have been predicted from database analyses, the process of alternative splicing and its regulatory machinery are hardly understood. We searched for and detected alternative splicing events that alter protein splicing in all or a subset of tumor tissues. The results revealed tissue-specific alterations of splicing regulation by tumorigenesis, and regulatory cis-element analyses further suggested that multiple splicing regulatory machineries were affected by this process.
Collapse
Affiliation(s)
- Masayo Okumura
- Division of Structural Cellular Biology, The Graduate School of Biological Sciences, Nara Institute of Science and Technology (NAIST), 8916-5 Takayama, Ikoma, Nara 630-0101, Japan.
| | | | | | | | | | | | | | | |
Collapse
|
47
|
Wiemann S, Kolb-Kokocinski A, Poustka A. Alternative pre-mRNA processing regulates cell-type specific expression of the IL4l1 and NUP62 genes. BMC Biol 2005; 3:16. [PMID: 16029492 PMCID: PMC1198218 DOI: 10.1186/1741-7007-3-16] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2005] [Accepted: 07/19/2005] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Given the complexity of higher organisms, the number of genes encoded by their genomes is surprisingly small. Tissue specific regulation of expression and splicing are major factors enhancing the number of the encoded products. Commonly these mechanisms are intragenic and affect only one gene. RESULTS Here we provide evidence that the IL4I1 gene is specifically transcribed from the apparent promoter of the upstream NUP62 gene, and that the first two exons of NUP62 are also contained in the novel IL4I1_2 variant. While expression of IL4I1 driven from its previously described promoter is found mostly in B cells, the expression driven by the NUP62 promoter is restricted to cells in testis (Sertoli cells) and in the brain (e.g., Purkinje cells). Since NUP62 is itself ubiquitously expressed, the IL4I1_2 variant likely derives from cell type specific alternative pre-mRNA processing. CONCLUSION Comparative genomics suggest that the promoter upstream of the NUP62 gene originally belonged to the IL4I1 gene and was later acquired by NUP62 via insertion of a retroposon. Since both genes are apparently essential, the promoter had to serve two genes afterwards. Expression of the IL4I1 gene from the "NUP62" promoter and the tissue specific involvement of the pre-mRNA processing machinery to regulate expression of two unrelated proteins indicate a novel mechanism of gene regulation.
Collapse
Affiliation(s)
- Stefan Wiemann
- Molecular Genome Analysis, German Cancer Research Center, Im Neuenheimer Feld 580, Heidelberg, 69120, Germany
| | - Anja Kolb-Kokocinski
- Molecular Genome Analysis, German Cancer Research Center, Im Neuenheimer Feld 580, Heidelberg, 69120, Germany
| | - Annemarie Poustka
- Molecular Genome Analysis, German Cancer Research Center, Im Neuenheimer Feld 580, Heidelberg, 69120, Germany
| |
Collapse
|
48
|
Pelisch F, Blaustein M, Kornblihtt AR, Srebrow A. Cross-talk between signaling pathways regulates alternative splicing: a novel role for JNK. J Biol Chem 2005; 280:25461-9. [PMID: 15886203 DOI: 10.1074/jbc.m412007200] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The regulation of alternative splicing by extracellular signals represents a key event in the control of gene expression. There is increasing evidence showing that many extracellular cues regulate alternative splicing. Nevertheless, the broad picture regarding the role of different signaling pathways and their interaction remains incomplete. Using the fibronectin gene as a model, we show that a laminin-rich basement membrane regulates the alternative splicing of two out of three regions of the transcript (extra domain I and type III connecting segment) in mammary epithelial cells, through a non-stress c-Jun N-terminal kinase (JNK) signaling pathway. We propose that dephosphorylation of the extracellular signal-regulated kinase is involved in this regulatory process. Furthermore, the laminin-rich basement membrane blocks the effect of a mammary mesenchymal cell-conditioned medium, which stimulates the inclusion of extra domain I and type III connecting segment through a phosphatidylinositol3-kinase-dependent cascade, indicating that JNK signaling can inhibit the phosphatidylinositol 3-kinase-mediated splicing regulation. These results implicate JNK in the regulation of alternative splicing and provide new evidence on how extracellular stimuli are converted into changes in splicing patterns, strengthening the view that the control of alternative splicing is as complex and relevant as transcriptional control, together accounting for the spatiotemporal requirements of gene expression.
Collapse
Affiliation(s)
- Federico Pelisch
- Biología Molecular y Neurociencias-Consejo Nacional de Investigaciones Científicas y Técnicas, Departamento de Fisiología, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Buenos Aires, Argentina
| | | | | | | |
Collapse
|