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Journal of Experimental Botany Mar 2022Flowering plants reproduce sexually by combining a haploid male and female gametophyte during fertilization. Male gametophytes are localized in the anthers, each...
Flowering plants reproduce sexually by combining a haploid male and female gametophyte during fertilization. Male gametophytes are localized in the anthers, each containing reproductive (meiocyte) and non-reproductive tissue necessary for anther development and maturation. Meiosis, where chromosomes pair and exchange their genetic material during a process called recombination, is one of the most important and sensitive stages in breeding, ensuring genetic diversity. Most anther development studies have focused on transcript variation, but very few have been correlated with protein abundance. Taking advantage of a recently published barley anther transcriptomic (BAnTr) dataset and a newly developed sensitive mass spectrometry-based approach to analyse the barley anther proteome, we conducted high-resolution mass spectrometry analysis of barley anthers, collected at six time points and representing their development from pre-meiosis to metaphase. Each time point was carefully staged using immunocytology, providing a robust and accurate staging mirroring our previous BAnTr dataset. We identified >6100 non-redundant proteins including 82 known and putative meiotic proteins. Although the protein abundance was relatively stable throughout prophase I, we were able to quantify the dynamic variation of 336 proteins. We present the first quantitative comparative proteomics study of barley anther development during meiotic prophase I when the important process of homologous recombination is taking place.
Topics: Flowers; Hordeum; Meiosis; Meiotic Prophase I; Plant Proteins; Proteome
PubMed: 34758083
DOI: 10.1093/jxb/erab494 -
Scientific Reports Sep 2022Spatiotemporal regulation of proteins and RNAs is essential for the precise development of reproductive tissues in many organisms. The anther, a prominent part of the...
Spatiotemporal regulation of proteins and RNAs is essential for the precise development of reproductive tissues in many organisms. The anther, a prominent part of the male reproductive organ in plants, contains several somatic cell layers named the anther wall and, within it, the germ cells. Here, we successfully developed a simple 3D organ-immunoimaging technique for rice anthers, which distinguishes each individual cell from the four somatic cell layers and germ cells without the need for transformation, embedding, sectioning, or clearing. The 3D immunostaining method is also applicable to the intracellular localization of meiosis-specific proteins in meiocytes, as exemplified by MEL1, a germ cell-specific ARGONAUTE in the cytoplasm, and ZEP1, a pachytene marker on meiotic chromosomes. Our 3D multiple immunostaining method with single-cell and intracellular resolution will contribute to a comprehensive organ-level elucidation of molecular mechanisms and cellular connectivity.
Topics: Argonaute Proteins; Meiosis; Meiotic Prophase I; Oryza; Pollen
PubMed: 36104379
DOI: 10.1038/s41598-022-19373-4 -
Frontiers in Cell and Developmental... 2022PLK1 is a serine/threonine kinase with crucial roles during mitosis. However, its involvement during mammalian male meiosis remains largely unexplored. By inhibiting the...
PLK1 is a serine/threonine kinase with crucial roles during mitosis. However, its involvement during mammalian male meiosis remains largely unexplored. By inhibiting the kinase activity of PLK1 using BI 2536 on organotypic cultures of seminiferous tubules, we found that the disassembly of SYCP3 and HORMAD1 from the lateral elements of the synaptonemal complex during diakinesis is impeded. We also found that the normal recruitment of SYCP3 and HORMAD1 to the inner centromere in prometaphase I spermatocytes did not occur. Additionally, we analyzed the participation of PLK1 in the assembly of the inner centromere by studying its implication in the Bub1-H2AT120ph-dependent recruitment of shugoshin SGO2, and the Haspin-H3T3ph-dependent recruitment of Aurora B/C and Borealin. Our results indicated that both pathways are regulated by PLK1. Altogether, our results demonstrate that PLK1 is a master regulator of the late prophase I/metaphase I transition in mouse spermatocytes.
PubMed: 36733339
DOI: 10.3389/fcell.2022.1069946 -
Cytometry. Part a : the Journal of the... Jun 2014
Topics: Animals; Flow Cytometry; Male; Meiotic Prophase I; Spermatocytes; Spermatogenesis
PubMed: 24664871
DOI: 10.1002/cyto.a.22468 -
Chromatin remodeler CHD8 is required for spermatogonial proliferation and early meiotic progression.Nucleic Acids Research Apr 2024Meiosis is a key step during germ cell differentiation, accompanied by the activation of thousands of genes through germline-specific chromatin reorganization. The...
Meiosis is a key step during germ cell differentiation, accompanied by the activation of thousands of genes through germline-specific chromatin reorganization. The chromatin remodeling mechanisms underpinning early meiotic stages remain poorly understood. Here we focus on the function of one of the major autism genes, CHD8, in spermatogenesis, based on the epidemiological association between autism and low fertility rates. Specific ablation of Chd8 in germ cells results in gradual depletion of undifferentiated spermatogonia and the failure of meiotic double-strand break (DSB) formation, leading to meiotic prophase I arrest and cell death. Transcriptional analyses demonstrate that CHD8 is required for extensive activation of spermatogenic genes in spermatogonia, necessary for spermatogonial proliferation and meiosis. CHD8 directly binds and regulates genes crucial for meiosis, including H3K4me3 histone methyltransferase genes, meiotic cohesin genes, HORMA domain-containing genes, synaptonemal complex genes, and DNA damage response genes. We infer that CHD8 contributes to meiotic DSB formation and subsequent meiotic progression through combined regulation of these meiosis-related genes. Our study uncovers an essential role of CHD8 in the proliferation of undifferentiated spermatogonia and the successful progression of meiotic prophase I.
Topics: Male; Cell Proliferation; Chromatin; Meiosis; Spermatogenesis; Spermatogonia; Animals; Mice
PubMed: 38224953
DOI: 10.1093/nar/gkad1256 -
Chromosoma Mar 2014Rapid chromosome movement during prophase of the first meiotic division has been observed in many organisms. It is generally concomitant with formation of the "meiotic... (Review)
Review
Rapid chromosome movement during prophase of the first meiotic division has been observed in many organisms. It is generally concomitant with formation of the "meiotic chromosome bouquet," a special chromosome configuration in which one or both chromosome ends attach to the nuclear envelope and become concentrated within a limited area. The precise function of the chromosomal bouquet is still not fully understood. Chromosome mobility is implicated in homologous chromosome pairing, synaptonemal complex formation, recombination, and resolution of chromosome entanglements. The basic mechanistic module through which forces are exerted on chromosomes is widely conserved; however, phenotypic differences have been reported among various model organisms once movement is abrogated. Movements are transmitted to the chromosome ends by the nuclear membrane-bridging SUN/KASH complex and are dependent on cytoskeletal filaments and motor proteins located in the cytoplasm. Here we review the recent findings on chromosome mobility during meiosis in an animal model system: the Caenorhabditis elegans nematode.
Topics: Animals; Caenorhabditis elegans; Chromosome Pairing; Chromosomes; Meiotic Prophase I; Movement; Pachytene Stage
PubMed: 24036686
DOI: 10.1007/s00412-013-0436-7 -
Chromosoma Dec 2022In most eukaryotes, pairing of homologous chromosomes is an essential feature of meiosis that ensures homologous recombination and segregation. However, when the pairing...
In most eukaryotes, pairing of homologous chromosomes is an essential feature of meiosis that ensures homologous recombination and segregation. However, when the pairing process begins, it is still under investigation. Contrasting data exists in Mus musculus, since both leptotene DSB-dependent and preleptotene DSB-independent mechanisms have been described. To unravel this contention, we examined homologous pairing in pre-meiotic and meiotic Mus musculus cells using a three-dimensional fluorescence in situ hybridization-based protocol, which enables the analysis of the entire karyotype using DNA painting probes. Our data establishes in an unambiguously manner that 73.83% of homologous chromosomes are already paired at premeiotic stages (spermatogonia-early preleptotene spermatocytes). The percentage of paired homologous chromosomes increases to 84.60% at mid-preleptotene-zygotene stage, reaching 100% at pachytene stage. Importantly, our results demonstrate a high percentage of homologous pairing observed before the onset of meiosis; this pairing does not occur randomly, as the percentage was higher than that observed in somatic cells (19.47%) and between nonhomologous chromosomes (41.1%). Finally, we have also observed that premeiotic homologous pairing is asynchronous and independent of the chromosome size, GC content, or presence of NOR regions.
Topics: Animals; Mice; Male; In Situ Hybridization, Fluorescence; Meiosis; Meiotic Prophase I; Karyotype; Spermatocytes
PubMed: 35960388
DOI: 10.1007/s00412-022-00777-0 -
Genes Mar 2022To generate gametes, sexually reproducing organisms need to achieve a reduction in ploidy, via meiosis. Several mechanisms are set in place to ensure proper reductional... (Review)
Review
To generate gametes, sexually reproducing organisms need to achieve a reduction in ploidy, via meiosis. Several mechanisms are set in place to ensure proper reductional chromosome segregation at the first meiotic division (MI), including chromosome remodeling during late prophase I. Chromosome remodeling after crossover formation involves changes in chromosome condensation and restructuring, resulting in a compact bivalent, with sister kinetochores oriented to opposite poles, whose structure is crucial for localized loss of cohesion and accurate chromosome segregation. Here, we review the general processes involved in late prophase I chromosome remodeling, their regulation, and the strategies devised by different organisms to produce bivalents with configurations that promote accurate segregation.
Topics: Chromosome Segregation; Kinetochores; Meiosis; Meiotic Prophase I
PubMed: 35328099
DOI: 10.3390/genes13030546 -
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 -
Frontiers in Cell and Developmental... 2021During meiotic prophase I, X and Y chromosomes in mammalian spermatocytes only stably pair at a small homologous region called the pseudoautosomal region (PAR). However,... (Review)
Review
During meiotic prophase I, X and Y chromosomes in mammalian spermatocytes only stably pair at a small homologous region called the pseudoautosomal region (PAR). However, the rest of the sex chromosomes remain largely unsynapsed. The extensive asynapsis triggers transcriptional silencing - meiotic sex chromosome inactivation (MSCI). Along with MSCI, a special nuclear territory, sex body or XY body, forms. In the early steps of MSCI, DNA damage response (DDR) factors, such as BRCA1, ATR, and γH2AX, function as sensors and effectors of the silencing signals. Downstream canonical repressive histone modifications, including methylation, acetylation, ubiquitylation, and SUMOylation, are responsible for the transcriptional repression of the sex chromosomes. Nevertheless, mechanisms of the sex-body formation remain unclear. Liquid-liquid phase separation (LLPS) may drive the formation of several chromatin subcompartments, such as pericentric heterochromatin, nucleoli, inactive X chromosomes. Although several proteins involved in phase separation are found in the sex bodies, when and whether these proteins exert functions in the sex-body formation and MSCI is still unknown. Here, we reviewed recent publications on the mechanisms of MSCI and LLPS, pointed out the potential link between LLPS and the formation of sex bodies, and discussed its implications for future research.
PubMed: 34485277
DOI: 10.3389/fcell.2021.674203