1
|
Frey T, Murakami T, Maki K, Kawaue T, Tani N, Sugai A, Nakazawa N, Ishiguro K, Adachi T, Kengaku M, Ohki K, Gotoh Y, Kishi Y. Age-associated reduction of nuclear shape dynamics in excitatory neurons of the visual cortex. Aging Cell 2023; 22:e13925. [PMID: 37476844 PMCID: PMC10497821 DOI: 10.1111/acel.13925] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Revised: 06/19/2023] [Accepted: 06/21/2023] [Indexed: 07/22/2023] Open
Abstract
Neurons decline in their functionality over time, and age-related neuronal alterations are associated with phenotypes of neurodegenerative diseases. In nonneural tissues, an infolded nuclear shape has been proposed as a hallmark of aged cells and neurons with infolded nuclei have also been reported to be associated with neuronal activity. Here, we performed time-lapse imaging in the visual cortex of Nex-Cre;SUN1-GFP mice. Nuclear infolding was observed within 10 min of stimulation in young nuclei, while the aged nuclei were already infolded pre-stimulation and showed reduced dynamics of the morphology. In young nuclei, the depletion of the stimuli restored the nucleus to a spherical shape and reduced the dynamic behavior, suggesting that nuclear infolding is a reversible process. We also found the aged nucleus to be stiffer than the young one, further relating to the age-associated loss of nuclear shape dynamics. We reveal temporal changes in the nuclear shape upon external stimulation and observe that these morphological dynamics decrease with age.
Collapse
Affiliation(s)
- Tanita Frey
- Graduate School of Pharmaceutical SciencesThe University of TokyoTokyoJapan
- New York University Grossman School of MedicineNew YorkNew YorkUSA
| | - Tomonari Murakami
- Graduate School of MedicineThe University of TokyoTokyoJapan
- Institute for AI and Beyond, The University of TokyoTokyoJapan
| | - Koichiro Maki
- Institute for Life and Medical Sciences, Kyoto UniversityKyotoJapan
| | - Takumi Kawaue
- Institute for Integrated Cell‐Material Sciences, Institute for Advanced Study, Kyoto UniversityKyotoJapan
| | - Naoki Tani
- Liaison Laboratory Research Promotion CenterIMEG, Kumamoto UniversityKumamotoJapan
| | - Ayaka Sugai
- Graduate School of Pharmaceutical SciencesThe University of TokyoTokyoJapan
- Institute for Quantitative Biosciences, The University of TokyoTokyoJapan
| | - Naotaka Nakazawa
- Institute for Integrated Cell‐Material Sciences, Institute for Advanced Study, Kyoto UniversityKyotoJapan
- Department of Energy and Materials, Faculty of Science and EngineeringKindai UniversityOsakaJapan
| | - Kei‐ichiro Ishiguro
- Department of Chromosome BiologyInstitute of Molecular Embryology and Genetics (IMEG), Kumamoto UniversityKumamotoJapan
| | - Taiji Adachi
- Institute for Life and Medical Sciences, Kyoto UniversityKyotoJapan
| | - Mineko Kengaku
- Institute for Integrated Cell‐Material Sciences, Institute for Advanced Study, Kyoto UniversityKyotoJapan
| | - Kenichi Ohki
- Graduate School of MedicineThe University of TokyoTokyoJapan
- Institute for AI and Beyond, The University of TokyoTokyoJapan
- International Research Center for Neurointelligence (WPI‐IRCN), The University of TokyoTokyoJapan
| | - Yukiko Gotoh
- Graduate School of Pharmaceutical SciencesThe University of TokyoTokyoJapan
- International Research Center for Neurointelligence (WPI‐IRCN), The University of TokyoTokyoJapan
| | - Yusuke Kishi
- Graduate School of Pharmaceutical SciencesThe University of TokyoTokyoJapan
- Institute for Quantitative Biosciences, The University of TokyoTokyoJapan
| |
Collapse
|
2
|
Paukszto Ł, Wiśniewska J, Liszewska E, Majewska M, Jastrzębski J, Jankowski J, Ciereszko A, Słowińska M. Specific expression of alternatively spliced genes in the turkey (Meleagris gallopavo) reproductive tract revealed their function in spermatogenesis and post-testicular sperm maturation. Poult Sci 2023; 102:102484. [PMID: 36709584 PMCID: PMC9922982 DOI: 10.1016/j.psj.2023.102484] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Revised: 12/22/2022] [Accepted: 01/03/2023] [Indexed: 01/12/2023] Open
Abstract
The tissue-specific profile of alternatively spliced genes (ASGs) and their involvement in reproduction processes characteristic of turkey testis, epididymis, and ductus deferens were investigated for the first time in birds. Deep sequencing of male turkey reproductive tissue RNA samples (n = 6) was performed using Illumina RNA-Seq with 2 independent methods, rMATs and SUPPA2, for differential alternative splicing (DAS) event prediction. The expression of selected ASGs was validated using quantitative real-time reverse transcriptase-polymerase chain reaction. The testis was found to be the site of the highest number of posttranscriptional splicing events within the reproductive tract, and skipping exons were the most frequently occurring class of alternative splicing (AS) among the reproductive tract. Statistical analysis revealed 86, 229, and 6 DAS events in the testis/epididymis, testis/ductus deferens, and epididymis/ductus deferens comparison, respectively. Alternative splicing was found to be a mechanism of gene expression regulation within the turkey reproduction tract. In testis, modification was observed for spermatogenesis specific genes; the changes in 5' UTR could act as regulator of MEIG1 expression (a player during spermatocytes meiosis), and modification of 3' UTR led to diversification of CREM mRNA (modulator of gene expression related to the structuring of mature spermatozoa). Sperm tail formation can be regulated by changes in the 5' UTR of testicular SLC9A3R1 and gene silencing by producing dysfunctional variants of ODF2 in the testis and ATP1B3 in the epididymis. Predicted differentially ASGs in the turkey reproductive tract seem to be involved in the regulation of spermatogenesis, including acrosome formation and sperm tail formation and binding of sperm to the zona pellucida. Several ASGs were classified as cilia by actin and microtubule cytoskeleton organization. Such genes may play a role in the organization of sperm flagellum and post-testicular motility development. To our knowledge, this is the first functional investigation of alternatively spliced genes associated with tissue-specific processes in the turkey reproductive tract.
Collapse
Affiliation(s)
- Łukasz Paukszto
- Department of Botany and Nature Protection, Faculty of Biology and Biotechnology; University of Warmia and Mazury in Olsztyn, 10-719, Olsztyn, Poland
| | - Joanna Wiśniewska
- Department of Biological Function of Food, Institute of Animal Reproduction and Food Research, Polish Academy of Sciences in Olsztyn, 10-748, Olsztyn, Poland
| | - Ewa Liszewska
- Department of Gamete and Embryo Biology, Institute of Animal Reproduction and Food Research, Polish Academy of Sciences in Olsztyn, 10-748, Olsztyn, Poland
| | - Marta Majewska
- Department of Human Physiology and Pathophysiology, School of Medicine, Collegium Medicum; University of Warmia and Mazury in Olsztyn, 10-561 Olsztyn, Poland
| | - Jan Jastrzębski
- Department of Plant Physiology, Genetics, and Biotechnology, Faculty of Biology and Biotechnology, University of Warmia and Mazury in Olsztyn, 10-719, Olsztyn, Poland
| | - Jan Jankowski
- Department of Poultry Science, University of Warmia and Mazury in Olsztyn, 10-719, Olsztyn, Poland
| | - Andrzej Ciereszko
- Department of Gamete and Embryo Biology, Institute of Animal Reproduction and Food Research, Polish Academy of Sciences in Olsztyn, 10-748, Olsztyn, Poland
| | - Mariola Słowińska
- Department of Gamete and Embryo Biology, Institute of Animal Reproduction and Food Research, Polish Academy of Sciences in Olsztyn, 10-748, Olsztyn, Poland.
| |
Collapse
|
3
|
Caballero D, Brancato V, Lima AC, Abreu CM, Neves NM, Correlo VM, Oliveira JM, Reis RL, Kundu SC. Tumor-Associated Protrusion Fluctuations as a Signature of Cancer Invasiveness. Adv Biol (Weinh) 2021; 5:e2101019. [PMID: 34218529 DOI: 10.1002/adbi.202101019] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 06/21/2021] [Indexed: 12/14/2022]
Abstract
The generation of invasive fluctuating protrusions is a distinctive feature of tumor dissemination. During the invasion, individual cancer cells modulate the morphodynamics of protrusions to optimize their migration efficiency. However, it remains unclear how protrusion fluctuations govern the invasion of more complex multi-cellular structures, such as tumors, and their correlation with the tumor metastatic potential. Herein, a reductionist approach based on 3D tumor cell micro-spheroids with different invasion capabilities is used as a model to decipher the role of tumor-associated fluctuating protrusions in cancer progression. To quantify fluctuations, a set of key biophysical parameters that precisely correlate with the invasive potential of tumors is defined. It is shown that different pharmacological drugs and cytokines are capable of modulating protrusion activity, significantly altering protrusion fluctuations, and tumor invasiveness. This correlation is used to define a novel quantitative invasion index encoding the key biophysical parameters of fluctuations and the relative levels of cell-cell/matrix interactions, which is capable of assessing the tumor's metastatic capability solely based on its magnitude. Overall, this study provides new insights into how protrusion fluctuations regulate tumor cell invasion, suggesting that they may be employed as a novel early indicator, or biophysical signature, of the metastatic potential of tumors.
Collapse
Affiliation(s)
- David Caballero
- 3B's Research Group, I3Bs - Research Institute on Biomaterials, Biodegradables and Biomimetics, University of Minho, Headquarters of the European Institute of Excellence on Tissue Engineering and Regenerative Medicine, Barco, Guimarães, 4805-017, Portugal.,ICVS/3B's, PT Government Associate Laboratory, Braga, Guimarães, 4805-017, Portugal
| | - Virginia Brancato
- 3B's Research Group, I3Bs - Research Institute on Biomaterials, Biodegradables and Biomimetics, University of Minho, Headquarters of the European Institute of Excellence on Tissue Engineering and Regenerative Medicine, Barco, Guimarães, 4805-017, Portugal.,ICVS/3B's, PT Government Associate Laboratory, Braga, Guimarães, 4805-017, Portugal
| | - Ana C Lima
- 3B's Research Group, I3Bs - Research Institute on Biomaterials, Biodegradables and Biomimetics, University of Minho, Headquarters of the European Institute of Excellence on Tissue Engineering and Regenerative Medicine, Barco, Guimarães, 4805-017, Portugal.,ICVS/3B's, PT Government Associate Laboratory, Braga, Guimarães, 4805-017, Portugal
| | - Catarina M Abreu
- 3B's Research Group, I3Bs - Research Institute on Biomaterials, Biodegradables and Biomimetics, University of Minho, Headquarters of the European Institute of Excellence on Tissue Engineering and Regenerative Medicine, Barco, Guimarães, 4805-017, Portugal.,ICVS/3B's, PT Government Associate Laboratory, Braga, Guimarães, 4805-017, Portugal
| | - Nuno M Neves
- 3B's Research Group, I3Bs - Research Institute on Biomaterials, Biodegradables and Biomimetics, University of Minho, Headquarters of the European Institute of Excellence on Tissue Engineering and Regenerative Medicine, Barco, Guimarães, 4805-017, Portugal.,ICVS/3B's, PT Government Associate Laboratory, Braga, Guimarães, 4805-017, Portugal
| | - Vitor M Correlo
- 3B's Research Group, I3Bs - Research Institute on Biomaterials, Biodegradables and Biomimetics, University of Minho, Headquarters of the European Institute of Excellence on Tissue Engineering and Regenerative Medicine, Barco, Guimarães, 4805-017, Portugal.,ICVS/3B's, PT Government Associate Laboratory, Braga, Guimarães, 4805-017, Portugal
| | - Joaquim M Oliveira
- 3B's Research Group, I3Bs - Research Institute on Biomaterials, Biodegradables and Biomimetics, University of Minho, Headquarters of the European Institute of Excellence on Tissue Engineering and Regenerative Medicine, Barco, Guimarães, 4805-017, Portugal.,ICVS/3B's, PT Government Associate Laboratory, Braga, Guimarães, 4805-017, Portugal
| | - Rui L Reis
- 3B's Research Group, I3Bs - Research Institute on Biomaterials, Biodegradables and Biomimetics, University of Minho, Headquarters of the European Institute of Excellence on Tissue Engineering and Regenerative Medicine, Barco, Guimarães, 4805-017, Portugal.,ICVS/3B's, PT Government Associate Laboratory, Braga, Guimarães, 4805-017, Portugal
| | - Subhas C Kundu
- 3B's Research Group, I3Bs - Research Institute on Biomaterials, Biodegradables and Biomimetics, University of Minho, Headquarters of the European Institute of Excellence on Tissue Engineering and Regenerative Medicine, Barco, Guimarães, 4805-017, Portugal.,ICVS/3B's, PT Government Associate Laboratory, Braga, Guimarães, 4805-017, Portugal
| |
Collapse
|
4
|
Satomi E, Ueda M, Katahira J, Hieda M. The SUN1 splicing variants SUN1_888 and SUN1_916 differentially regulate nucleolar structure. Genes Cells 2020; 25:730-740. [PMID: 32931086 DOI: 10.1111/gtc.12807] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 08/27/2020] [Accepted: 09/07/2020] [Indexed: 12/22/2022]
Abstract
The nucleolar structure is highly dynamic and strictly regulated in response to internal cues, such as metabolic rates, and to external cues, such as mechanical forces applied to cells. Although the multilayered nucleolar structure is largely determined by the liquid-like properties of RNA and proteins, the mechanisms regulating the morphology and number of nucleoli remain elusive. The linker of the nucleoskeleton and cytoskeleton (LINC) complex comprises inner nuclear membrane Sad1/UNC-84 (SUN) proteins and outer nuclear membrane-localized nesprins. We previously showed that the depletion of SUN1 proteins affects nucleolar morphologies. This study focuses on the function of SUN1 splicing variants in determining nucleolar morphology. An RNA interference strategy showed that the predominantly expressed variants, SUN1_888 and SUN1_916, were crucial for nucleolar morphology but functionally distinct. In addition, the depletion of either SUN1_888 or SUN1_916 altered the chromatin structure and affected the distribution of histone modifications. Based on these results, we propose a model in which the LINC complex plays a role in modulating nucleolar morphology and numbers via chromatin.
Collapse
Affiliation(s)
- Erina Satomi
- Graduate School of Health Sciences, Ehime Prefectural University of Health Sciences, Ehime, Japan
| | - Masako Ueda
- Graduate School of Health Sciences, Ehime Prefectural University of Health Sciences, Ehime, Japan
| | - Jun Katahira
- Department of Veterinary Sciences, Osaka Prefecture University, Osaka, Japan
| | - Miki Hieda
- Graduate School of Health Sciences, Ehime Prefectural University of Health Sciences, Ehime, Japan
| |
Collapse
|
5
|
Almendáriz-Palacios C, Gillespie ZE, Janzen M, Martinez V, Bridger JM, Harkness TAA, Mousseau DD, Eskiw CH. The Nuclear Lamina: Protein Accumulation and Disease. Biomedicines 2020; 8:E188. [PMID: 32630170 PMCID: PMC7400325 DOI: 10.3390/biomedicines8070188] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Revised: 06/23/2020] [Accepted: 06/26/2020] [Indexed: 02/06/2023] Open
Abstract
Cellular health is reliant on proteostasis-the maintenance of protein levels regulated through multiple pathways modulating protein synthesis, degradation and clearance. Loss of proteostasis results in serious disease and is associated with aging. One proteinaceous structure underlying the nuclear envelope-the nuclear lamina-coordinates essential processes including DNA repair, genome organization and epigenetic and transcriptional regulation. Loss of proteostasis within the nuclear lamina results in the accumulation of proteins, disrupting these essential functions, either via direct interactions of protein aggregates within the lamina or by altering systems that maintain lamina structure. Here we discuss the links between proteostasis and disease of the nuclear lamina, as well as how manipulating specific proteostatic pathways involved in protein clearance could improve cellular health and prevent/reverse disease.
Collapse
Affiliation(s)
- Carla Almendáriz-Palacios
- Department of Food and Bioproduct Sciences, University of Saskatchewan, Saskatoon, SK S7N 5A8, Canada; (C.A.-P.); (V.M.)
| | - Zoe E. Gillespie
- Department of Biochemistry, Microbiology and Immunology, University of Saskatchewan, Saskatoon, SK S7N 5A8, Canada; (Z.E.G.); (M.J.); (T.A.A.H.)
| | - Matthew Janzen
- Department of Biochemistry, Microbiology and Immunology, University of Saskatchewan, Saskatoon, SK S7N 5A8, Canada; (Z.E.G.); (M.J.); (T.A.A.H.)
| | - Valeria Martinez
- Department of Food and Bioproduct Sciences, University of Saskatchewan, Saskatoon, SK S7N 5A8, Canada; (C.A.-P.); (V.M.)
| | - Joanna M. Bridger
- Centre for Genome Engineering and Maintenance, College of Health, Life and Medical Sciences, Brunel University London, Kingston Lane, Uxbridge UB8 3PH, UK;
| | - Troy A. A. Harkness
- Department of Biochemistry, Microbiology and Immunology, University of Saskatchewan, Saskatoon, SK S7N 5A8, Canada; (Z.E.G.); (M.J.); (T.A.A.H.)
| | - Darrell D. Mousseau
- Cell Signalling Laboratory, Department of Psychiatry, University of Saskatchewan, Saskatoon, SK S7N 5A5, Canada;
| | - Christopher H. Eskiw
- Department of Food and Bioproduct Sciences, University of Saskatchewan, Saskatoon, SK S7N 5A8, Canada; (C.A.-P.); (V.M.)
- Department of Biochemistry, Microbiology and Immunology, University of Saskatchewan, Saskatoon, SK S7N 5A8, Canada; (Z.E.G.); (M.J.); (T.A.A.H.)
| |
Collapse
|
6
|
In Vitro Cytotoxicity Effects of Zinc Oxide Nanoparticles on Spermatogonia Cells. Cells 2020; 9:cells9051081. [PMID: 32357578 PMCID: PMC7290761 DOI: 10.3390/cells9051081] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Revised: 04/23/2020] [Accepted: 04/24/2020] [Indexed: 12/12/2022] Open
Abstract
Zinc Oxide Nanoparticles (ZnO NPs) are a type of metal oxide nanoparticle with an extensive use in biomedicine. Several studies have focused on the biosafety of ZnO NPs, since their size and surface area favor entrance and accumulation in the body, which can induce toxic effects. In previous studies, ZnO NPs have been identified as a dose- and time-dependent cytotoxic inducer in testis and male germ cells. However, the consequences for the first cell stage of spermatogenesis, spermatogonia, have never been evaluated. Therefore, the aim of the present work is to evaluate in vitro the cytotoxic effects of ZnO NPs in spermatogonia cells, focusing on changes in cytoskeleton and nucleoskeleton. For that purpose, GC-1 cell line derived from mouse testes was selected as a model of spermatogenesis. These cells were treated with different doses of ZnO NPs for 6 h and 12 h. The impact of GC-1 cells exposure to ZnO NPs on cell viability, cell damage, and cytoskeleton and nucleoskeleton dynamics was assessed. Our results clearly indicate that higher concentrations of ZnO NPs have a cytotoxic effect in GC-1 cells, leading to an increase of intracellular Reactive Oxygen Species (ROS) levels, DNA damage, cytoskeleton and nucleoskeleton dynamics alterations, and consequently cell death. In conclusion, it is here reported for the first time that ZnO NPs induce cytotoxic effects, including changes in cytoskeleton and nucleoskeleton in mouse spermatogonia cells, which may compromise the progression of spermatogenesis in a time- and dose-dependent manner.
Collapse
|
7
|
Loo TH, Ye X, Chai RJ, Ito M, Bonne G, Ferguson-Smith AC, Stewart CL. The mammalian LINC complex component SUN1 regulates muscle regeneration by modulating drosha activity. eLife 2019; 8:49485. [PMID: 31686651 PMCID: PMC6853637 DOI: 10.7554/elife.49485] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Accepted: 10/27/2019] [Indexed: 01/13/2023] Open
Abstract
Here we show that a major muscle specific isoform of the murine LINC complex protein SUN1 is required for efficient muscle regeneration. The nucleoplasmic domain of the isoform specifically binds to and inhibits Drosha, a key component of the microprocessor complex required for miRNA synthesis. Comparison of the miRNA profiles between wildtype and SUN1 null myotubes identified a cluster of miRNAs encoded by a non-translated retrotransposon-like one antisense (Rtl1as) transcript that are decreased in the WT myoblasts due to SUN1 inhibition of Drosha. One of these miRNAs miR-127 inhibits the translation of the Rtl1 sense transcript, that encodes the retrotransposon-like one protein (RTL1), which is also required for muscle regeneration and is expressed in regenerating/dystrophic muscle. The LINC complex may therefore regulate gene expression during muscle regeneration by controlling miRNA processing. This provides new insights into the molecular pathology underlying muscular dystrophies and how the LINC complex may regulate mechanosignaling.
Collapse
Affiliation(s)
- Tsui Han Loo
- Developmental and Regenerative Biology, Institute of Medical Biology, Singapore, Singapore
| | - Xiaoqian Ye
- Developmental and Regenerative Biology, Institute of Medical Biology, Singapore, Singapore
| | - Ruth Jinfen Chai
- Developmental and Regenerative Biology, Institute of Medical Biology, Singapore, Singapore
| | - Mitsuteru Ito
- Department of Genetics, University of Cambridge, Cambridge, United Kingdom
| | - Gisèle Bonne
- Center of Research in Myology, Institut de Myologie, Sorbonne Universités, UPMC Univ Paris 06, INSERM UMRS 974, CNRS FRE 3617, Paris, France
| | | | - Colin L Stewart
- Developmental and Regenerative Biology, Institute of Medical Biology, Singapore, Singapore
| |
Collapse
|
8
|
Detection of SUN1 Splicing Variants at the mRNA and Protein Levels in Cancer. Methods Mol Biol 2018. [PMID: 30141053 DOI: 10.1007/978-1-4939-8691-0_21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
The linker of nucleoskeleton and cytoskeleton (LINC) complex, containing the proteins SUN and nesprin, is the fundamental structural unit of the nuclear envelope. The neoplastic-based regulation of the LINC complex in cancer tissues has become increasingly recognized in recent years, including the altered expression, somatic mutation, and methylation of genes. However, precisely how mutations and deregulated expression of the LINC complex contribute to the pathogenic mechanisms of tumorigenesis remain to be elucidated, mainly because of several technical difficulties. First, both the SUN and SYNE (encoding nesprin) genes give rise to a vast number of splicing variants. Second, immunoprecipitation experiments of endogenous SUN and nesprin proteins are difficult owing to the lack of suitable reagents as well as the limited solubility of these proteins in mild extraction conditions. Here, we describe three protocols to investigate these aspects: (1) immunohistochemistry to determine the expression levels and localization of the LINC complex in cancer tissue, (2) detection of SUN1 splicing variants at the mRNA level, and (3) detection of SUN1 splicing variants and binding partners at the protein level.
Collapse
|
9
|
Zeng X, Li K, Yuan R, Gao H, Luo J, Liu F, Wu Y, Wu G, Yan X. Nuclear Envelope-Associated Chromosome Dynamics during Meiotic Prophase I. Front Cell Dev Biol 2018; 5:121. [PMID: 29376050 PMCID: PMC5767173 DOI: 10.3389/fcell.2017.00121] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Accepted: 12/21/2017] [Indexed: 12/21/2022] Open
Abstract
Chromosome dynamics during meiotic prophase I are associated with a series of major events such as chromosomal reorganization and condensation, pairing/synapsis and recombination of the homologs, and chromosome movements at the nuclear envelope (NE). The NE is the barrier separating the nucleus from the cytoplasm and thus plays a central role in NE-associated chromosomal movements during meiosis. Previous studies have shown in various species that NE-linked chromosome dynamics are actually driven by the cytoskeleton. The linker of nucleoskeleton and cytoskeleton (LINC) complexes are important constituents of the NE that facilitate in the transfer of cytoskeletal forces across the NE to individual chromosomes. The LINCs consist of the inner and outer NE proteins Sad1/UNC-84 (SUN), and Klarsicht/Anc-1/Syne (KASH) domain proteins. Meiosis-specific adaptations of the LINC components and unique modifications of the NE are required during chromosomal movements. Nonetheless, the actual role of the NE in chromosomic dynamic movements in plants remains elusive. This review summarizes the findings of recent studies on meiosis-specific constituents and modifications of the NE and corresponding nucleoplasmic/cytoplasmic adaptors being involved in NE-associated movement of meiotic chromosomes, as well as describes the potential molecular network of transferring cytoplasm-derived forces into meiotic chromosomes in model organisms. It helps to gain a better understanding of the NE-associated meiotic chromosomal movements in plants.
Collapse
Affiliation(s)
- Xinhua Zeng
- Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture, Wuhan, China
| | - Keqi Li
- Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture, Wuhan, China
| | - Rong Yuan
- Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture, Wuhan, China
| | - Hongfei Gao
- Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture, Wuhan, China
| | - Junling Luo
- Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture, Wuhan, China
| | - Fang Liu
- Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture, Wuhan, China
| | - Yuhua Wu
- Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture, Wuhan, China
| | - Gang Wu
- Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture, Wuhan, China
| | - Xiaohong Yan
- Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture, Wuhan, China
| |
Collapse
|
10
|
Effects of Inner Nuclear Membrane Proteins SUN1/UNC-84A and SUN2/UNC-84B on the Early Steps of HIV-1 Infection. J Virol 2017; 91:JVI.00463-17. [PMID: 28747499 PMCID: PMC5599759 DOI: 10.1128/jvi.00463-17] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Accepted: 07/18/2017] [Indexed: 12/25/2022] Open
Abstract
Human immunodeficiency virus type 1 (HIV-1) infection of dividing and nondividing cells involves regulatory interactions with the nuclear pore complex (NPC), followed by translocation to the nucleus and preferential integration into genomic areas in proximity to the inner nuclear membrane (INM). To identify host proteins that may contribute to these processes, we performed an overexpression screen of known membrane-associated NE proteins. We found that the integral transmembrane proteins SUN1/UNC84A and SUN2/UNC84B are potent or modest inhibitors of HIV-1 infection, respectively, and that suppression corresponds to defects in the accumulation of viral cDNA in the nucleus. While laboratory strains (HIV-1NL4.3 and HIV-1IIIB) are sensitive to SUN1-mediated inhibition, the transmitted founder viruses RHPA and ZM247 are largely resistant. Using chimeric viruses, we identified the HIV-1 capsid (CA) protein as a major determinant of sensitivity to SUN1, and in vitro-assembled capsid-nucleocapsid (CANC) nanotubes captured SUN1 and SUN2 from cell lysates. Finally, we generated SUN1−/− and SUN2−/− cells by using CRISPR/Cas9 and found that the loss of SUN1 had no effect on HIV-1 infectivity, whereas the loss of SUN2 had a modest suppressive effect. Taken together, these observations suggest that SUN1 and SUN2 may function redundantly to modulate postentry, nuclear-associated steps of HIV-1 infection. IMPORTANCE HIV-1 causes more than 1 million deaths per year. The life cycle of HIV-1 has been studied extensively, yet important steps that occur between viral capsid release into the cytoplasm and the expression of viral genes remain elusive. We propose here that the INM components SUN1 and SUN2, two members of the linker of nucleoskeleton and cytoskeleton (LINC) complex, may interact with incoming HIV-1 replication complexes and affect key steps of infection. While overexpression of these proteins reduces HIV-1 infection, disruption of the individual SUN2 and SUN1 genes leads to a mild reduction or no effect on infectivity, respectively. We speculate that SUN1/SUN2 may function redundantly in early HIV-1 infection steps and therefore influence HIV-1 replication and pathogenesis.
Collapse
|
11
|
Moujaber O, Omran N, Kodiha M, Pié B, Cooper E, Presley JF, Stochaj U. Data on the association of the nuclear envelope protein Sun1 with nucleoli. Data Brief 2017; 13:115-123. [PMID: 28580408 PMCID: PMC5447391 DOI: 10.1016/j.dib.2017.05.028] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2016] [Revised: 05/10/2017] [Accepted: 05/11/2017] [Indexed: 11/01/2022] Open
Abstract
SUN proteins participate in diverse cellular activities, many of which are connected to the nuclear envelope. Recently, the family member SUN1 has been linked to novel biological activities. These include the regulation of nucleoli, intranuclear compartments that assemble ribosomal subunits. We show that SUN1 associates with nucleoli in several mammalian epithelial cell lines. This nucleolar localization is not shared by all cell types, as SUN1 concentrates at the nuclear envelope in ganglionic neurons and non-neuronal satellite cells. Database analyses and Western blotting emphasize the complexity of SUN1 protein profiles in different mammalian cells. We constructed a STRING network which identifies SUN1-related proteins as part of a larger network that includes several nucleolar proteins. Taken together, the current data highlight the diversity of SUN1 proteins and emphasize the possible links between SUN1 and nucleoli.
Collapse
Affiliation(s)
| | - Nawal Omran
- Physiology, McGill University, Montreal, Canada
| | | | | | | | - John F Presley
- Anatomy & Cell Biology, McGill University, Montreal, Canada
| | | |
Collapse
|
12
|
Nishioka Y, Imaizumi H, Imada J, Katahira J, Matsuura N, Hieda M. SUN1 splice variants, SUN1_888, SUN1_785, and predominant SUN1_916, variably function in directional cell migration. Nucleus 2017; 7:572-584. [PMID: 27858498 DOI: 10.1080/19491034.2016.1260802] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
Abstract
The LINC complex is a multifunctional protein complex that is involved in various processes at the nuclear envelope, such as nuclear migration, mechanotransduction and chromatin tethering in the meiotic phase. However, it remains unknown how these functions are regulated in different cell contexts. An inner nuclear membrane component of the LINC complex, SUN1, is ubiquitously expressed. The human SUN1 gene produces over 10 variants by alternative splicing. Although functions of SUN1 are relatively well characterized, functional differences among SUN1 splice variants are poorly characterized. LINC complex components are associated with a wide range of human diseases; therefore, it is important to understand the functional diversity among SUN1 splice variants. Here, we identified a novel human SUN1 splice variant, SUN1_888. overexpression of the SUN1 splice variants, SUN1_888 or SUN1_785, but not the predominant isoform, SUN1_916, activated directional cell migration. Knockdown of SUN1_888 suppressed cell migration; in contrast depletion of SUN1_916 activated cell migration. In addition, all of investigated SUN1 splicing variants rescued cell migration in SUN1 knock out cell. These results indicate that redundant and non-redundant functions of SUN1 splice variant in directional cell migration and suggest that variable LINC complexes with distinct task may exit. Furthermore, in contrast to previous studies, we showed association between SUN1 and B-type lamins. Interestingly, B-type lamin preferentially interacts with SUN1 but not SUN2. These results suggest that tissue-specific SUN1 variants variably interact with nucleoplasmic partners and allow variable assembly of LINC complexes that can be assigned to distinct tasks.
Collapse
Affiliation(s)
- Yu Nishioka
- a Osaka University, Graduate School of Medicine and Health Science , Suita City , Osaka , Japan
| | - Hiromasa Imaizumi
- a Osaka University, Graduate School of Medicine and Health Science , Suita City , Osaka , Japan
| | - Junko Imada
- a Osaka University, Graduate School of Medicine and Health Science , Suita City , Osaka , Japan
| | - Jun Katahira
- b Osaka University, Graduate School of Frontier Bioscience , Suita City , Osaka , Japan
| | - Nariaki Matsuura
- a Osaka University, Graduate School of Medicine and Health Science , Suita City , Osaka , Japan
| | - Miki Hieda
- a Osaka University, Graduate School of Medicine and Health Science , Suita City , Osaka , Japan.,c Ehime Prefectural University of Health Science s, Tobe-cho , Ehime , Japan
| |
Collapse
|
13
|
Thakar K, May CK, Rogers A, Carroll CW. Opposing roles for distinct LINC complexes in regulation of the small GTPase RhoA. Mol Biol Cell 2016; 28:182-191. [PMID: 28035049 PMCID: PMC5221622 DOI: 10.1091/mbc.e16-06-0467] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Revised: 09/20/2016] [Accepted: 11/02/2016] [Indexed: 12/01/2022] Open
Abstract
Different forms of nuclear envelope–spanning LINC complexes have opposing roles in the transcription-independent control of the small GTPase RhoA. Competition between LINC complexes in the nuclear envelope may therefore dictate the outcome of signaling to cytoskeletal networks. Linker of Nucleoskeleton and Cytoskeleton (LINC) complexes span the nuclear envelope and transduce force from dynamic cytoskeletal networks to the nuclear lamina. Here we show that LINC complexes also signal from the nuclear envelope to critical regulators of the actin cytoskeleton. Specifically, we find that LINC complexes that contain the inner nuclear membrane protein Sun2 promote focal adhesion assembly by activating the small GTPase RhoA. A key effector in this process is the transcription factor/coactivator complex composed of SRF/Mkl1. A constitutively active form of SRF/Mkl1 was not sufficient to induce focal adhesion assembly in cells lacking Sun2, however, suggesting that LINC complexes support RhoA activity through a transcription-independent mechanism. Strikingly, we also find that the inner nuclear membrane protein Sun1 antagonizes Sun2 LINC complexes and inhibits RhoA activation and focal adhesion assembly. Thus different LINC complexes have opposing roles in the transcription-independent control of the actin cytoskeleton through the small GTPase RhoA.
Collapse
Affiliation(s)
- Ketan Thakar
- Department of Cell Biology, Yale School of Medicine, New Haven, CT 06520
| | - Christopher K May
- Department of Cell Biology, Yale School of Medicine, New Haven, CT 06520
| | - Anna Rogers
- Department of Cell Biology, Yale School of Medicine, New Haven, CT 06520
| | | |
Collapse
|
14
|
SUN4 is essential for nuclear remodeling during mammalian spermiogenesis. Dev Biol 2015; 407:321-30. [DOI: 10.1016/j.ydbio.2015.09.010] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2015] [Revised: 08/27/2015] [Accepted: 09/23/2015] [Indexed: 11/17/2022]
|
15
|
Link J, Jahn D, Alsheimer M. Structural and functional adaptations of the mammalian nuclear envelope to meet the meiotic requirements. Nucleus 2015; 6:93-101. [PMID: 25674669 PMCID: PMC4615672 DOI: 10.1080/19491034.2015.1004941] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Numerous studies in the past years provided definite evidence that the nuclear envelope is much more than just a simple barrier. It rather constitutes a multifunctional platform combining structural and dynamic features to fulfill many fundamental functions such as chromatin organization, regulation of transcription, signaling, but also structural duties like maintaining general nuclear architecture and shape. One additional and, without doubt, highly impressive aspect is the recently identified key function of selected nuclear envelope components in driving meiotic chromosome dynamics, which in turn is essential for accurate recombination and segregation of the homologous chromosomes. Here, we summarize the recent work identifying new key players in meiotic telomere attachment and movement and discuss the latest advances in our understanding of the actual function of the meiotic nuclear envelope.
Collapse
Affiliation(s)
- Jana Link
- a Department of Cell and Developmental Biology ; Biocenter University Würzburg ; Würzburg , Germany
| | | | | |
Collapse
|
16
|
Meinke P, Mattioli E, Haque F, Antoku S, Columbaro M, Straatman KR, Worman HJ, Gundersen GG, Lattanzi G, Wehnert M, Shackleton S. Muscular dystrophy-associated SUN1 and SUN2 variants disrupt nuclear-cytoskeletal connections and myonuclear organization. PLoS Genet 2014; 10:e1004605. [PMID: 25210889 PMCID: PMC4161305 DOI: 10.1371/journal.pgen.1004605] [Citation(s) in RCA: 125] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2013] [Accepted: 07/16/2014] [Indexed: 11/19/2022] Open
Abstract
Proteins of the nuclear envelope (NE) are associated with a range of inherited disorders, most commonly involving muscular dystrophy and cardiomyopathy, as exemplified by Emery-Dreifuss muscular dystrophy (EDMD). EDMD is both genetically and phenotypically variable, and some evidence of modifier genes has been reported. Six genes have so far been linked to EDMD, four encoding proteins associated with the LINC complex that connects the nucleus to the cytoskeleton. However, 50% of patients have no identifiable mutations in these genes. Using a candidate approach, we have identified putative disease-causing variants in the SUN1 and SUN2 genes, also encoding LINC complex components, in patients with EDMD and related myopathies. Our data also suggest that SUN1 and SUN2 can act as disease modifier genes in individuals with co-segregating mutations in other EDMD genes. Five SUN1/SUN2 variants examined impaired rearward nuclear repositioning in fibroblasts, confirming defective LINC complex function in nuclear-cytoskeletal coupling. Furthermore, myotubes from a patient carrying compound heterozygous SUN1 mutations displayed gross defects in myonuclear organization. This was accompanied by loss of recruitment of centrosomal marker, pericentrin, to the NE and impaired microtubule nucleation at the NE, events that are required for correct myonuclear arrangement. These defects were recapitulated in C2C12 myotubes expressing exogenous SUN1 variants, demonstrating a direct link between SUN1 mutation and impairment of nuclear-microtubule coupling and myonuclear positioning. Our findings strongly support an important role for SUN1 and SUN2 in muscle disease pathogenesis and support the hypothesis that defects in the LINC complex contribute to disease pathology through disruption of nuclear-microtubule association, resulting in defective myonuclear positioning. Emery-Dreifuss muscular dystrophy (EDMD) is an inherited disorder involving muscle wasting and weakness, accompanied by cardiac defects. The disease is variable in its severity and also in its genetic cause. So far, 6 genes have been linked to EDMD, most encoding proteins that form a structural network that supports the nucleus of the cell and connects it to structural elements of the cytoplasm. This network is particularly important in muscle cells, providing resistance to mechanical strain. Weakening of this network is thought to contribute to development of muscle disease in these patients. Despite rigorous screening, at least 50% of patients with EDMD have no detectable mutation in the 6 known genes. We therefore undertook screening and identified mutations in two additional genes that encode other components of the nuclear structural network, SUN1 and SUN2. Our findings add to the genetic complexity of this disease since some individuals carry mutations in more than one gene. We also show that the mutations disrupt connections between the nucleus and the structural elements of cytoplasm, leading to mis-positioning and clustering of nuclei in muscle cells. This nuclear mis-positioning is likely to be another factor contributing to pathogenesis of EDMD.
Collapse
Affiliation(s)
- Peter Meinke
- Institute of Human Genetics and Interfaculty Institute of Genetics and Functional Genomics, University of Greifswald, Greifswald, Germany
| | - Elisabetta Mattioli
- National Research Council of Italy - CNR - Institute for Molecular Genetics, Unit of Bologna IOR, Bologna, Italy
- Rizzoli Orthopaedic Institute, Laboratory of Musculoskeletal Cell Biology, Bologna, Italy
| | - Farhana Haque
- Department of Biochemistry, University of Leicester, Leicester, United Kingdom
| | - Susumu Antoku
- Department of Pathology and Cell Biology, College of Physicians and Surgeons, Columbia University, New York, New York, United States of America
| | - Marta Columbaro
- Rizzoli Orthopaedic Institute, Laboratory of Musculoskeletal Cell Biology, Bologna, Italy
| | - Kees R. Straatman
- Centre for Core Biotechnology Services, University of Leicester, Leicester, United Kingdom
| | - Howard J. Worman
- Department of Pathology and Cell Biology, College of Physicians and Surgeons, Columbia University, New York, New York, United States of America
- Department of Medicine, College of Physicians and Surgeons, Columbia University, New York, New York, United States of America
| | - Gregg G. Gundersen
- Department of Pathology and Cell Biology, College of Physicians and Surgeons, Columbia University, New York, New York, United States of America
| | - Giovanna Lattanzi
- National Research Council of Italy - CNR - Institute for Molecular Genetics, Unit of Bologna IOR, Bologna, Italy
- Rizzoli Orthopaedic Institute, Laboratory of Musculoskeletal Cell Biology, Bologna, Italy
| | - Manfred Wehnert
- Institute of Human Genetics and Interfaculty Institute of Genetics and Functional Genomics, University of Greifswald, Greifswald, Germany
| | - Sue Shackleton
- Department of Biochemistry, University of Leicester, Leicester, United Kingdom
- * E-mail:
| |
Collapse
|
17
|
Stroud MJ, Banerjee I, Veevers J, Chen J. Linker of nucleoskeleton and cytoskeleton complex proteins in cardiac structure, function, and disease. Circ Res 2014; 114:538-48. [PMID: 24481844 DOI: 10.1161/circresaha.114.301236] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The linker of nucleoskeleton and cytoskeleton (LINC) complex, composed of proteins within the inner and the outer nuclear membranes, connects the nuclear lamina to the cytoskeleton. The importance of this complex has been highlighted by the discovery of mutations in genes encoding LINC complex proteins, which cause skeletal or cardiac myopathies. Herein, this review summarizes structure, function, and interactions of major components of the LINC complex, highlights how mutations in these proteins may lead to cardiac disease, and outlines future challenges in the field.
Collapse
Affiliation(s)
- Matthew J Stroud
- From the Department of Cardiology, University of California San Diego School of Medicine, La Jolla, CA
| | | | | | | |
Collapse
|
18
|
|
19
|
Razafsky D, Wirtz D, Hodzic D. Nuclear envelope in nuclear positioning and cell migration. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2014; 773:471-90. [PMID: 24563361 PMCID: PMC4310828 DOI: 10.1007/978-1-4899-8032-8_21] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Hauling and anchoring the nucleus within immobile or motile cells, tissues, and/or syncytia represents a major challenge. In the past 15 years, Linkers of the Nucleoskeleton to the Cytoskeleton (LINC complexes) have emerged as evolutionary-conserved molecular devices that span the nuclear envelope and provide interacting interfaces for cytoskeletal networks and molecular motors to the nuclear envelope. Here, we review the molecular composition of LINC complexes and focus on how their genetic alteration in vivo has provided a wealth of information related to the relevance of nuclear positioning during tissue development and homeostasis with a special emphasis on the central nervous system. As it may be relevant for metastasis in a range of cancers, the involvement of LINC complexes in migration of nonneuronal cells via its interaction with the perinuclear actin cap will also be developed.
Collapse
Affiliation(s)
- David Razafsky
- Washington University School of Medicine, Department of Ophthalmology and Visual Sciences, 660 South Euclid Ave, St Louis, MO, 63110, USA
| | - Denis Wirtz
- The Johns Hopkins University, Department of Chemical and Biomolecular engineering, 3400 North Charles St., Baltimore, MD, 21218, USA
| | - Didier Hodzic
- Washington University School of Medicine, Department of Ophthalmology and Visual Sciences, 660 South Euclid Ave, St Louis, MO, 63110, USA
| |
Collapse
|
20
|
Razafsky DS, Ward CL, Kolb T, Hodzic D. Developmental regulation of linkers of the nucleoskeleton to the cytoskeleton during mouse postnatal retinogenesis. Nucleus 2013; 4:399-409. [PMID: 23974729 DOI: 10.4161/nucl.26244] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Sun proteins and Nesprins are two families of proteins whose direct interactions across the nuclear envelope provide for the core of Linkers of the Nucleoskeleton to the Cytoskeleton (LINC complexes) that physically connect the nucleus interior to cytoskeletal networks. Whereas LINC complexes play essential roles in nuclear migration anchorage and underlie normal CNS development, the developmental regulation of their composition remains largely unknown. In this study, we examined the spatiotemporal expression of lamins, Sun proteins and Nesprins during postnatal mouse retinal development. Whereas retinal precursor cells mostly express B-type lamins, Sun1, and high molecular weight isoforms of Nesprins, post-mitotic retinal cells are characterized by a drastic downregulation of the latter, the expression of A-type lamins, and the strong induction of a specific isoform of Nesprin1 late in retinal development. Importantly, our results emphasize different spatiotemporal expression for Nesprin1 and Nesprin2 and further suggest an important role for KASH-less isoforms of Nesprin1 in the CNS. In conclusion, the transition from retinal precursor cells undergoing interkinetic nuclear migration to post-mitotic retinal cells undergoing nuclear translocation and/or anchorage is accompanied by a profound remodeling of LINC complexes composition. This remodeling may reflect different requirements of nuclear dynamics at different stages of CNS development.
Collapse
Affiliation(s)
- David S Razafsky
- Department of Ophthalmology and Visual Sciences; Washington University School of Medicine; St Louis, MO USA; Division of Molecular Genetics; German Cancer Research Center (DKFZ); Heidelberg, Germany
| | | | | | | |
Collapse
|
21
|
Abstract
Gametogenesis combines two important features: reduction of the genome content from diploid to haploid by carefully partitioning chromosomes, and the subsequent differentiation into fertilization-competent gametes, which in males is characterized by profound nuclear restructuring. These are quite difficult tasks and require a tight coordination of different cellular mechanisms. Recent studies in the field established a key role for LINC complexes in both meiosis and sperm head formation. LINC complexes comprise SUN and KASH domain proteins that form nuclear envelope (NE) bridges, linking the nucleoskeleton to the cytoskeleton. They are well known for their crucial roles in diverse cellular and developmental processes, such as nuclear positioning and cell polarization. In this review, we highlight key roles ascribed to LINC complexes and to the nucleocytoskeletal connection in gametogenesis. First, we give a short overview about the general features of LINC components and the profound reorganization of the NE in germ cells. We then focus on specific roles of LINC complexes in meiotic chromosome dynamics and their impact on pairing, synapsis, and recombination. Finally, we provide an update of the mechanisms controlling sperm head formation and discuss the role of sperm-specific LINC complexes in nuclear shaping and their relation to specialized cytoskeletal structures that form concurrently with nuclear restructuring and sperm elongation.
Collapse
Affiliation(s)
- Martin P Kracklauer
- Department of Physiology, Wayne State University Medical School, Detroit, Michigan, USA
| | | | | |
Collapse
|