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Sheng Li Xue Bao : [Acta Physiologica... Feb 2020Meiosis is a special type of cell division to produce haploid gametes with intact genome. The behavior of homologous chromosomes during the first division (meiosis... (Review)
Review
Meiosis is a special type of cell division to produce haploid gametes with intact genome. The behavior of homologous chromosomes during the first division (meiosis prophase I) is the most prominent feature of meiosis. During meiosis prophase I, synaptonemal complex (SC) formed between homologous chromosomes to promote the initiation and repair of programmed DNA double-strand breaks (DSBs), which is necessary for the correct recognition, pairing, recombination and separation of homologous chromosomes. In this paper, we reviewed the recent research progress on the composition and function of SC, discussed how the assembly of SC affected the repair of DSBs, and also summarized the known mutations on SC genes which were responsible for human reproductive disorders. On this basis, we also explored the future research direction of this field.
Topics: DNA Breaks, Double-Stranded; DNA Repair; Humans; Meiotic Prophase I; Synaptonemal Complex
PubMed: 32099986
DOI: No ID Found -
Current Topics in Developmental Biology 2023Chromosomes adopt specific conformations to regulate various cellular processes. A well-documented chromosome configuration is the highly compacted chromosome structure... (Review)
Review
Chromosomes adopt specific conformations to regulate various cellular processes. A well-documented chromosome configuration is the highly compacted chromosome structure during metaphase. More regional chromatin conformations have also been reported, including topologically associated domains encompassing mega-bases of DNA and local chromatin loops formed by kilo-bases of DNA. In this review, we discuss the changes in chromatin conformation taking place between somatic and meiotic cells, with a special focus on the establishment of a proteinaceous structure, called the chromosome axis, at the beginning of meiosis. The chromosome axis is essential to support key meiotic processes such as chromosome pairing, homologous recombination, and balanced chromosome segregation to transition from a diploid to a haploid stage. We review the role of the chromosome axis in meiotic chromatin organization and provide a detailed description of its protein composition. We also review the conserved and distinct roles between species of axis proteins in meiotic recombination, which is a major factor contributing to the creation of genetic diversity and genome evolution. Finally, we discuss situations where the chromosome axis is deregulated and evaluate the effects on genome integrity and the consequences from protein deregulation in meiocytes exposed to heat stress, and aberrant expression of genes encoding axis proteins in mammalian somatic cells associated with certain types of cancers.
Topics: Animals; Synaptonemal Complex; Meiosis; Chromosome Pairing; Chromatin; Neoplasms; Mammals
PubMed: 36681479
DOI: 10.1016/bs.ctdb.2022.04.008 -
Current Topics in Developmental Biology 2023Meiosis is critical for germ cell development in multicellular organisms. Initiation of meiosis coincides with pre-meiotic S phase, which is followed by meiotic... (Review)
Review
Meiosis is critical for germ cell development in multicellular organisms. Initiation of meiosis coincides with pre-meiotic S phase, which is followed by meiotic prophase, a prolonged G2 phase that ensures numerous meiosis-specific chromosome events. Meiotic prophase is accompanied by robust alterations of gene expression. In mouse germ cells, MEIOSIN and STRA8 direct cell cycle switch from mitosis to meiosis. MEIOSIN and STRA8 coordinate meiotic initiation with cell cycle, by activating the meiotic genes to have meiotic prophase program installed at S phase. This review mainly focuses on the mechanism of meiotic initiation in mouse germ cells from the viewpoint of the transcription of meiotic genes. Furthermore, signaling pathways that regulate meiotic initiation will be discussed in the context of germ cell development, pointing out the sexual differences in the mode of meiotic initiation.
Topics: Mice; Animals; Meiosis; Adaptor Proteins, Signal Transducing; Mitosis; Signal Transduction; Germ Cells
PubMed: 36681467
DOI: 10.1016/bs.ctdb.2022.04.005 -
Molecular Aspects of Medicine Jun 2024Meiosis is a critical step for spermatogenesis and oogenesis. Meiosis commences with pre-meiotic S phase that is subsequently followed by meiotic prophase. The meiotic... (Review)
Review
Meiosis is a critical step for spermatogenesis and oogenesis. Meiosis commences with pre-meiotic S phase that is subsequently followed by meiotic prophase. The meiotic prophase is characterized by the meiosis-specific chromosomal events such as chromosome recombination and homolog synapsis. Meiosis initiator (MEIOSIN) and stimulated by retinoic acid gene 8 (STRA8) initiate meiosis by activating the meiotic genes by installing the meiotic prophase program at pre-meiotic S phase. This review highlights the mechanisms of meiotic initiation and meiotic prophase progression from the point of the gene expression program and its relevance to infertility. Furthermore, upstream pathways that regulate meiotic initiation will be discussed in the context of spermatogenic development, indicating the sexual differences in the mode of meiotic entry.
Topics: Spermatogenesis; Humans; Meiosis; Animals; Male; Meiotic Prophase I; Prophase
PubMed: 38797021
DOI: 10.1016/j.mam.2024.101282 -
Chromosoma Sep 2019Accurate segregation of homologous chromosomes during meiosis depends on the ability of meiotic cells to promote reciprocal exchanges between parental DNA strands, known... (Review)
Review
Accurate segregation of homologous chromosomes during meiosis depends on the ability of meiotic cells to promote reciprocal exchanges between parental DNA strands, known as crossovers (COs). For most organisms, including budding yeast and other fungi, mammals, nematodes, and plants, the major CO pathway depends on ZMM proteins, a set of molecular actors specifically devoted to recognize and stabilize CO-specific DNA intermediates that are formed during homologous recombination. The progressive implementation of ZMM-dependent COs takes place within the context of the synaptonemal complex (SC), a proteinaceous structure that polymerizes between homologs and participates in close homolog juxtaposition during prophase I of meiosis. While SC polymerization starts from ZMM-bound sites and ZMM proteins are required for SC polymerization in budding yeast and the fungus Sordaria, other organisms differ in their requirement for ZMM in SC elongation. This review provides an overview of ZMM functions and discusses their collaborative tasks for CO formation and SC assembly, based on recent findings and on a comparison of different model organisms.
Topics: Carrier Proteins; Chromosome Pairing; Crossing Over, Genetic; DNA Breaks, Double-Stranded; DNA-Binding Proteins; Homologous Recombination; Meiosis; Phenotype; Protein Binding; Protein Interaction Mapping; Protein Interaction Maps; Protein Multimerization; Saccharomyces cerevisiae
PubMed: 31236671
DOI: 10.1007/s00412-019-00714-8 -
Cell Jun 2020Meiosis is the specialized cell division that generates haploid gametes and is therefore essential for sexual reproduction. This SnapShot encompasses key events taking...
Meiosis is the specialized cell division that generates haploid gametes and is therefore essential for sexual reproduction. This SnapShot encompasses key events taking place during prophase I of meiosis that are required for achieving proper chromosome segregation and highlights how these are both conserved and diverged throughout five different species. To view this SnapShot, open or download the PDF.
Topics: Animals; Arabidopsis; Caenorhabditis elegans; Chromosome Segregation; Drosophila melanogaster; Meiosis; Meiotic Prophase I; Mice; Saccharomyces cerevisiae
PubMed: 32531249
DOI: 10.1016/j.cell.2020.04.038 -
ELife Jan 2021Protein modification by SUMO helps orchestrate the elaborate events of meiosis to faithfully produce haploid gametes. To date, only a handful of meiotic SUMO targets...
Protein modification by SUMO helps orchestrate the elaborate events of meiosis to faithfully produce haploid gametes. To date, only a handful of meiotic SUMO targets have been identified. Here, we delineate a multidimensional SUMO-modified meiotic proteome in budding yeast, identifying 2747 conjugation sites in 775 targets, and defining their relative levels and dynamics. Modified sites cluster in disordered regions and only a minority match consensus motifs. Target identities and modification dynamics imply that SUMOylation regulates all levels of chromosome organization and each step of meiotic prophase I. Execution-point analysis confirms these inferences, revealing functions for SUMO in S-phase, the initiation of recombination, chromosome synapsis and crossing over. K15-linked SUMO chains become prominent as chromosomes synapse and recombine, consistent with roles in these processes. SUMO also modifies ubiquitin, forming hybrid oligomers with potential to modulate ubiquitin signaling. We conclude that SUMO plays diverse and unanticipated roles in regulating meiotic chromosome metabolism.
Topics: Chromosome Pairing; Meiosis; Prophase; SUMO-1 Protein; Saccharomyces cerevisiae; Saccharomyces cerevisiae Proteins; Sumoylation
PubMed: 33502312
DOI: 10.7554/eLife.57720 -
Trends in Genetics : TIG Nov 2020The synaptonemal complex (SC), a highly conserved structure built between homologous meiotic chromosomes, is required for crossover formation and ensuring proper... (Review)
Review
The synaptonemal complex (SC), a highly conserved structure built between homologous meiotic chromosomes, is required for crossover formation and ensuring proper chromosome segregation. In many organisms, SC components can also form alternative structures, including repeating SC structures that are known as polycomplexes (PCs), and extensively modified SC structures that are maintained late in meiosis. PCs display differences in their ability to localize with lateral element proteins, recombination machinery, and DNA. They can be created by defects in post-translational modification, suggesting that these modifications have roles in preventing alternate SC structures. These SC-like structures provide insight into the rules for building and maintaining the SC by offering an 'in vivo laboratory' for models of SC assembly, structure, and disassembly. Here, we discuss what these structures can tell us about the rules for building the SC and the roles of the SC in meiotic processes.
Topics: Animals; Chromosome Pairing; Chromosome Segregation; Crossing Over, Genetic; Humans; Meiosis; Nuclear Proteins; Synaptonemal Complex
PubMed: 32800626
DOI: 10.1016/j.tig.2020.07.007 -
The EMBO Journal Jun 2023During meiosis, chromosomes with homologous partners undergo synaptonemal complex (SC)-mediated pairing, while the remaining unpaired chromosomes are heterochromatinized...
During meiosis, chromosomes with homologous partners undergo synaptonemal complex (SC)-mediated pairing, while the remaining unpaired chromosomes are heterochromatinized through unpaired silencing. Mechanisms underlying homolog recognition during SC formation are still unclear. Here, we show that the Caenorhabditis elegans Argonaute proteins, CSR-1 and its paralog CSR-2, interacting with 22G-RNAs, are required for synaptonemal complex formation with accurate homology. CSR-1 in nuclei and meiotic cohesin, constituting the SC lateral elements, were associated with nonsimple DNA repeats, including minisatellites and transposons, and weakly associated with coding genes. CSR-1-associated CeRep55 minisatellites were expressing 22G-RNAs and long noncoding (lnc) RNAs that colocalized with synaptonemal complexes on paired chromosomes and with cohesin regions of unpaired chromosomes. CeRep55 multilocus deletions reduced the efficiencies of homologous pairing and unpaired silencing, which were supported by the csr-1 activity. Moreover, CSR-1 and CSR-2 were required for proper heterochromatinization of unpaired chromosomes. These findings suggest that CSR-1 and CSR-2 play crucial roles in homology recognition, achieving accurate SC formation between chromosome pairs and condensing unpaired chromosomes by targeting repeat-derived lncRNAs.
Topics: Animals; Caenorhabditis elegans; RNA; Chromosomes; Caenorhabditis elegans Proteins; Chromosome Pairing; Synaptonemal Complex; Meiosis
PubMed: 37078421
DOI: 10.15252/embj.2020105002 -
Current Topics in Developmental Biology 2023Sexual reproduction and the specialized cell division it relies upon, meiosis, are biological processes that present an incredible degree of both evolutionary... (Review)
Review
Sexual reproduction and the specialized cell division it relies upon, meiosis, are biological processes that present an incredible degree of both evolutionary conservation and divergence. One clear example of this paradox is the role of the evolutionarily ancient PCH-2/HORMAD module during meiosis. On one hand, the complex, and sometimes disparate, meiotic defects observed when PCH-2 and/or the meiotic HORMADS are mutated in different model systems have prevented a straightforward characterization of their conserved functions. On the other hand, these functional variations demonstrate the impressive molecular rewiring that accompanies evolution of the meiotic processes these factors are involved in. While the defects observed in pch-2 mutants appear to vary in different systems, in this review, I argue that PCH-2 has a conserved meiotic function: to coordinate meiotic recombination with synapsis to ensure an appropriate number and distribution of crossovers. Further, given the dramatic variation in how the events of recombination and synapsis are themselves regulated in different model systems, the mechanistic differences in PCH-2 and meiotic HORMAD function make biological sense when viewed as species-specific elaborations layered onto this fundamental, conserved role.
Topics: Adenosine Triphosphatases; Meiosis; Chromosome Pairing
PubMed: 36681475
DOI: 10.1016/bs.ctdb.2022.07.001