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Carmo C, Coelho J, Silva RD, Tavares A, Boavida A, Gaetani P, Guilgur LG, Martinho RG, Oliveira RA. A dual-function SNF2 protein drives chromatid resolution and nascent transcripts removal in mitosis. EMBO Rep 2023; 24:e56463. [PMID: 37462213 PMCID: PMC10481674 DOI: 10.15252/embr.202256463] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Revised: 06/28/2023] [Accepted: 07/03/2023] [Indexed: 09/07/2023] Open
Abstract
Mitotic chromatin is largely assumed incompatible with transcription due to changes in the transcription machinery and chromosome architecture. However, the mechanisms of mitotic transcriptional inactivation and their interplay with chromosome assembly remain largely unknown. By monitoring ongoing transcription in Drosophila early embryos, we reveal that eviction of nascent mRNAs from mitotic chromatin occurs after substantial chromosome compaction and is not promoted by condensin I. Instead, we show that the timely removal of transcripts from mitotic chromatin is driven by the SNF2 helicase-like protein Lodestar (Lds), identified here as a modulator of sister chromatid cohesion defects. In addition to the eviction of nascent transcripts, we uncover that Lds cooperates with Topoisomerase 2 to ensure efficient sister chromatid resolution and mitotic fidelity. We conclude that the removal of nascent transcripts upon mitotic entry is not a passive consequence of cell cycle progression and/or chromosome compaction but occurs via dedicated mechanisms with functional parallelisms to sister chromatid resolution.
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Affiliation(s)
| | - João Coelho
- Instituto Gulbenkian de CiênciaOeirasPortugal
| | - Rui D Silva
- Algarve Biomedical Center Research Institute (ABC‐RI) and Faculty of Medicine and Biomedical Sciences (FMCB)Universidade do AlgarveFaroPortugal
| | | | - Ana Boavida
- Instituto Gulbenkian de CiênciaOeirasPortugal
- Present address:
Istituto di Biochimica e Biologia Cellulare, Consiglio Nazionale delle RicercheNaplesItaly
| | | | | | - Rui Gonçalo Martinho
- Algarve Biomedical Center Research Institute (ABC‐RI) and Faculty of Medicine and Biomedical Sciences (FMCB)Universidade do AlgarveFaroPortugal
- Department of Medical Sciences (DCM) and Institute for Biomedicine (iBiMED)Universidade de AveiroAveiroPortugal
| | - Raquel A Oliveira
- Instituto Gulbenkian de CiênciaOeirasPortugal
- Católica Biomedical Research Centre, Católica Medical SchoolUniversidade Católica PortuguesaLisbonPortugal
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Xie C, Wang W, Tu C, Meng L, Lu G, Lin G, Lu LY, Tan YQ. OUP accepted manuscript. Hum Reprod Update 2022; 28:763-797. [PMID: 35613017 DOI: 10.1093/humupd/dmac024] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Revised: 04/18/2022] [Indexed: 11/12/2022] Open
Affiliation(s)
- Chunbo Xie
- Institute of Reproduction and Stem Cell Engineering, School of Basic Medical Science, Central South University, Changsha, China
- Clinical Research Center for Reproduction and Genetics in Hunan Province, Reproductive and Genetic Hospital of CITIC-Xiangya, Changsha, China
| | - Weili Wang
- Institute of Reproduction and Stem Cell Engineering, School of Basic Medical Science, Central South University, Changsha, China
| | - Chaofeng Tu
- Institute of Reproduction and Stem Cell Engineering, School of Basic Medical Science, Central South University, Changsha, China
- Clinical Research Center for Reproduction and Genetics in Hunan Province, Reproductive and Genetic Hospital of CITIC-Xiangya, Changsha, China
- NHC Key Laboratory of Human Stem Cell and Reproductive Engineering, Central South University, Changsha, China
- College of Life Sciences, Hunan Normal University, Changsha, China
| | - Lanlan Meng
- Institute of Reproduction and Stem Cell Engineering, School of Basic Medical Science, Central South University, Changsha, China
- Clinical Research Center for Reproduction and Genetics in Hunan Province, Reproductive and Genetic Hospital of CITIC-Xiangya, Changsha, China
| | - Guangxiu Lu
- Institute of Reproduction and Stem Cell Engineering, School of Basic Medical Science, Central South University, Changsha, China
- Clinical Research Center for Reproduction and Genetics in Hunan Province, Reproductive and Genetic Hospital of CITIC-Xiangya, Changsha, China
- NHC Key Laboratory of Human Stem Cell and Reproductive Engineering, Central South University, Changsha, China
- College of Life Sciences, Hunan Normal University, Changsha, China
| | - Ge Lin
- Institute of Reproduction and Stem Cell Engineering, School of Basic Medical Science, Central South University, Changsha, China
- Clinical Research Center for Reproduction and Genetics in Hunan Province, Reproductive and Genetic Hospital of CITIC-Xiangya, Changsha, China
- NHC Key Laboratory of Human Stem Cell and Reproductive Engineering, Central South University, Changsha, China
- College of Life Sciences, Hunan Normal University, Changsha, China
| | - Lin-Yu Lu
- Key Laboratory of Reproductive Genetics (Ministry of Education) and Women's Reproductive Health Laboratory of Zhejiang Province, Women's Hospital, Zhejiang University School of Medicine, Hangzhou, China
- Institute of Translational Medicine, Zhejiang University School of Medicine, Hangzhou, China
| | - Yue-Qiu Tan
- Institute of Reproduction and Stem Cell Engineering, School of Basic Medical Science, Central South University, Changsha, China
- Clinical Research Center for Reproduction and Genetics in Hunan Province, Reproductive and Genetic Hospital of CITIC-Xiangya, Changsha, China
- NHC Key Laboratory of Human Stem Cell and Reproductive Engineering, Central South University, Changsha, China
- College of Life Sciences, Hunan Normal University, Changsha, China
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3
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Vernizzi L, Lehner CF. Bivalent individualization during chromosome territory formation in Drosophila spermatocytes by controlled condensin II protein activity and additional force generators. PLoS Genet 2021; 17:e1009870. [PMID: 34669718 PMCID: PMC8559962 DOI: 10.1371/journal.pgen.1009870] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Revised: 11/01/2021] [Accepted: 10/11/2021] [Indexed: 12/12/2022] Open
Abstract
Reduction of genome ploidy from diploid to haploid necessitates stable pairing of homologous chromosomes into bivalents before the start of the first meiotic division. Importantly, this chromosome pairing must avoid interlocking of non-homologous chromosomes. In spermatocytes of Drosophila melanogaster, where homolog pairing does not involve synaptonemal complex formation and crossovers, associations between non-homologous chromosomes are broken up by chromosome territory formation in early spermatocytes. Extensive non-homologous associations arise from the coalescence of the large blocks of pericentromeric heterochromatin into a chromocenter and from centromere clustering. Nevertheless, during territory formation, bivalents are moved apart into spatially separate subnuclear regions. The condensin II subunits, Cap-D3 and Cap-H2, have been implicated, but the remarkable separation of bivalents during interphase might require more than just condensin II. For further characterization of this process, we have applied time-lapse imaging using fluorescent markers of centromeres, telomeres and DNA satellites in pericentromeric heterochromatin. We describe the dynamics of the disruption of centromere clusters and the chromocenter in normal spermatocytes. Mutations in Cap-D3 and Cap-H2 abolish chromocenter disruption, resulting in excessive chromosome missegregation during M I. Chromocenter persistence in the mutants is not mediated by the special system, which conjoins homologs in compensation for the absence of crossovers in Drosophila spermatocytes. However, overexpression of Cap-H2 precluded conjunction between autosomal homologs, resulting in random segregation of univalents. Interestingly, Cap-D3 and Cap-H2 mutant spermatocytes displayed conspicuous stretching of the chromocenter, as well as occasional chromocenter disruption, suggesting that territory formation might involve forces unrelated to condensin II. While the molecular basis of these forces remains to be clarified, they are not destroyed by inhibitors of F actin and microtubules. Our results indicate that condensin II activity promotes chromosome territory formation in co-operation with additional force generators and that careful co-ordination with alternative homolog conjunction is crucial.
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Affiliation(s)
- Luisa Vernizzi
- Department of Molecular Life Science (DMLS), University of Zurich, Zurich, Switzerland
| | - Christian F. Lehner
- Department of Molecular Life Science (DMLS), University of Zurich, Zurich, Switzerland
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4
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Hassan A, Araguas Rodriguez P, Heidmann SK, Walmsley EL, Aughey GN, Southall TD. Condensin I subunit Cap-G is essential for proper gene expression during the maturation of post-mitotic neurons. eLife 2020; 9:e55159. [PMID: 32255428 PMCID: PMC7170655 DOI: 10.7554/elife.55159] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Accepted: 04/06/2020] [Indexed: 02/07/2023] Open
Abstract
Condensin complexes are essential for mitotic chromosome assembly and segregation during cell divisions, however, little is known about their functions in post-mitotic cells. Here we report a role for the condensin I subunit Cap-G in Drosophila neurons. We show that, despite not requiring condensin for mitotic chromosome compaction, post-mitotic neurons express Cap-G. Knockdown of Cap-G specifically in neurons (from their birth onwards) results in developmental arrest, behavioural defects, and dramatic gene expression changes, including reduced expression of a subset of neuronal genes and aberrant expression of genes that are not normally expressed in the developing brain. Knockdown of Cap-G in mature neurons results in similar phenotypes but to a lesser degree. Furthermore, we see dynamic binding of Cap-G at distinct loci in progenitor cells and differentiated neurons. Therefore, Cap-G is essential for proper gene expression in neurons and plays an important role during the early stages of neuronal development.
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Affiliation(s)
- Amira Hassan
- Department of Life Sciences, Imperial College LondonLondonUnited Kingdom
| | | | | | - Emma L Walmsley
- Department of Life Sciences, Imperial College LondonLondonUnited Kingdom
| | - Gabriel N Aughey
- Department of Life Sciences, Imperial College LondonLondonUnited Kingdom
| | - Tony D Southall
- Department of Life Sciences, Imperial College LondonLondonUnited Kingdom
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