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Current Opinion in Plant Biology Aug 2024Heat stress is one of the major constraints to plant growth and fertility. During the current climate crisis, heat waves have increased dramatically, and even more... (Review)
Review
Heat stress is one of the major constraints to plant growth and fertility. During the current climate crisis, heat waves have increased dramatically, and even more extreme conditions are predicted for the near future, considerably affecting ecosystems and seriously threatening world food security. Although heat is very well known to affect especially reproductive structures, little is known about how heat interferes with reproduction in comparison to somatic cells and tissues. Recently, the effect of heat on meiosis as a central process in sexual reproduction has been analyzed in molecular and cytological depth. Notably, these studies are not only important for applied research by laying the foundation for breeding heat-resilient crops, but also for fundamental research, revealing general regulatory mechanisms of recombination and chromosome segregation control.
Topics: Meiosis; Chromosome Segregation; Recombination, Genetic; Hot Temperature; Chromosomes, Plant
PubMed: 38749207
DOI: 10.1016/j.pbi.2024.102548 -
Genes Jan 2022Meiosis is critically different from mitosis in that during meiosis, pairing and segregation of homologous chromosomes occur. During meiosis, the morphology of sister... (Review)
Review
Meiosis is critically different from mitosis in that during meiosis, pairing and segregation of homologous chromosomes occur. During meiosis, the morphology of sister chromatids changes drastically, forming a prominent axial structure in the synaptonemal complex. The meiosis-specific cohesin complex plays a central role in the regulation of the processes required for recombination. In particular, the Rec8 subunit of the meiotic cohesin complex, which is conserved in a wide range of eukaryotes, has been analyzed for its function in modulating chromosomal architecture during the pairing and recombination of homologous chromosomes in meiosis. Here, we review the current understanding of Rec8 cohesin as a structural platform for meiotic chromosomes.
Topics: Cell Cycle Proteins; Chromatids; Chromosomal Proteins, Non-Histone; Meiosis; Cohesins
PubMed: 35205245
DOI: 10.3390/genes13020200 -
Biomedical Journal Apr 2020Premature ovarian insufficiency (POI) is a major cause of female infertility. It is a heterogeneous disease that affects about 1% of women under 40 years of age. POI may... (Review)
Review
Premature ovarian insufficiency (POI) is a major cause of female infertility. It is a heterogeneous disease that affects about 1% of women under 40 years of age. POI may be due to abnormal follicle stock formation, increased follicular atresia, impaired recruitment of dominant follicles, blocked follicular maturation or rapid depletion of the follicular stock. It remains idiopathic in most cases but the existence of familial cases shows that it can have a genetic origin. Next generation sequencing (NGS) strategies have allowed the identification of new genes involved in the etiology of POI. Here, I briefly describe some studies demonstrating that pathogenic variants in 'DNA repair and meiotic genes' underlie POI. Some of the examples show the power of the combination of classical genetics and NGS in the discovery of novel 'POI genes'.
Topics: DNA Repair; Female; Follicular Atresia; High-Throughput Nucleotide Sequencing; Humans; Meiosis; Mutation; Primary Ovarian Insufficiency
PubMed: 32381463
DOI: 10.1016/j.bj.2020.03.005 -
Genes May 2022During the early meiotic prophase, connections are established between chromosomes and cytoplasmic motors via a nuclear envelope bridge, known as a LINC (linker of... (Review)
Review
During the early meiotic prophase, connections are established between chromosomes and cytoplasmic motors via a nuclear envelope bridge, known as a LINC (linker of nucleoskeleton and cytoskeleton) complex. These widely conserved links can promote both chromosome and nuclear motions. Studies in diverse organisms have illuminated the molecular architecture of these connections, but important questions remain regarding how they contribute to meiotic processes. Here, we summarize the current knowledge in the field, outline the challenges in studying these chromosome dynamics, and highlight distinctive features that have been characterized in major model systems.
Topics: Chromosomes; Cytoskeleton; Meiosis; Microtubules; Nuclear Envelope
PubMed: 35627285
DOI: 10.3390/genes13050901 -
Development (Cambridge, England) Jul 2023Retinoic acid (RA) is the proposed mammalian 'meiosis inducing substance'. However, evidence for this role comes from studies in the fetal ovary, where germ cell...
Retinoic acid (RA) is the proposed mammalian 'meiosis inducing substance'. However, evidence for this role comes from studies in the fetal ovary, where germ cell differentiation and meiotic initiation are temporally inseparable. In the postnatal testis, these events are separated by more than 1 week. Exploiting this difference, we discovered that, although RA is required for spermatogonial differentiation, it is dispensable for the subsequent initiation, progression and completion of meiosis. Indeed, in the absence of RA, the meiotic transcriptome program in both differentiating spermatogonia and spermatocytes entering meiosis was largely unaffected. Instead, transcripts encoding factors required during spermiogenesis were aberrant during preleptonema, and the subsequent spermatid morphogenesis program was disrupted such that no sperm were produced. Taken together, these data reveal a RA-independent model for male meiotic initiation.
Topics: Animals; Female; Male; Testis; Tretinoin; Spermatogenesis; Spermatogonia; Spermatozoa; Meiosis; Mammals
PubMed: 37350382
DOI: 10.1242/dev.201638 -
Chromosoma Sep 2019Meiosis is the special division that produces haploid gametes, such as sperm and eggs. It involves a complex series of events that integrate large structural changes at...
Meiosis is the special division that produces haploid gametes, such as sperm and eggs. It involves a complex series of events that integrate large structural changes at the chromosome scale with fine regulation of recombination events in localized regions. To evaluate the complexity of these processes, the meiosis field covers a variety of disciplines and model organisms, making it an exciting and rapidly changing area of research. The field as a whole highlights both the conserved aspects of meiosis, as well as the marked diversity of the means taken to ensure that, ultimately, gametes will contain a balanced number of chromosomes and genetic diversity will have been produced. Studying meiosis is also critically important for the improvement of our human condition as errors of meiosis are a leading cause of infertility, miscarriage, and developmental disabilities. Finally, the complex chromosome behavior of meiosis is a genetically tractable paradigm, the study of which improves our understanding of many fundamental cellular processes including DNA repair, genome stability, cancer etiology, chromatin structure, and chromosome dynamics.This special issue on meiosis contains twenty-two papers, of which five are in-depth reviews that complement and put in context the experimental data presented in the seventeen original research articles. The content of this issue illustrates the diversity of topics covered by researchers in the field, ranging from the effects of environment and external factors on the success of meiosis, the cell cycle actors that control the meiotic divisions, the mechanism of chromosome segregation, and the mechanisms that ensure proper homologous chromosome pairing, recombination, and synapsis. Multiple organisms are covered. Also evident is the fact that more and more studies use multicellular organisms as a model system, in large part due to the increased availability of tools that were previously restricted to studies in budding and fission yeasts.
Topics: Animals; Chromosome Segregation; DNA Replication; Humans; Meiosis
PubMed: 31616989
DOI: 10.1007/s00412-019-00726-4 -
Genes Mar 2022The origin and inheritance of chromosome changes provide the essential foundation for natural selection and evolution. The evolutionary fate of chromosome changes... (Review)
Review
The origin and inheritance of chromosome changes provide the essential foundation for natural selection and evolution. The evolutionary fate of chromosome changes depends on the place and time of their emergence and is controlled by checkpoints in mitosis and meiosis. Estimating whether the altered genome can be passed to subsequent generations should be central when we consider a particular genome rearrangement. Through comparative analysis of chromosome rearrangements in soma and germ line, the potential impact of macromutations such as chromothripsis or chromoplexy appears to be fascinating. What happens with chromosomes during the early development, and which alterations lead to mosaicism are other poorly studied but undoubtedly essential issues. The evolutionary impact can be gained most effectively through chromosome rearrangements arising in male meiosis I and in female meiosis II, which are the last divisions following fertilization. The diversity of genome organization has unique features in distinct animals; the chromosome changes, their internal relations, and some factors safeguarding genome maintenance in generations under natural selection were considered for mammals.
Topics: Animals; Chromosome Aberrations; Chromosomes; Chromothripsis; Female; Germ Cells; Male; Mammals; Meiosis; Mitosis
PubMed: 35456408
DOI: 10.3390/genes13040602 -
Autophagy Jun 2022The role of meiotic proteasome-mediated degradation has been extensively studied. At the same time, macroautophagy/autophagy only emerged recently as an essential...
The role of meiotic proteasome-mediated degradation has been extensively studied. At the same time, macroautophagy/autophagy only emerged recently as an essential regulator for meiosis progression. Our recent publication showed that autophagy in meiotic cells exhibits a temporal pattern distinct from that in quiescent cells or mitotic cells under prolonged starvation. Importantly, autophagic activity oscillates during meiotic cell divisions, i.e., meiosis I and meiosis II, which can accelerate meiotic progression and increase sporulation efficiency. Our and assays revealed that the conserved phosphatase Cdc14 stimulates autophagy initiation during meiotic divisions, specifically in anaphase I and II, when a subpopulation of active Cdc14 relocates to the cytosol and interacts with phagophore assembly sites (PAS) triggering the dephosphorylation of Atg13 to stimulate Atg1 kinase activity and autophagy. Together, our findings reveal a mechanism for the coordination of autophagy activity in the context of meiosis progression.
Topics: Adaptor Proteins, Signal Transducing; Autophagy; Autophagy-Related Proteins; Meiosis; Saccharomyces cerevisiae Proteins
PubMed: 35617128
DOI: 10.1080/15548627.2022.2080956 -
Cellular and Molecular Life Sciences :... Apr 2021Meiotic drive, the non-Mendelian transmission of chromosomes to the next generation, functions in asymmetric or symmetric meiosis across unicellular and multicellular... (Review)
Review
Meiotic drive, the non-Mendelian transmission of chromosomes to the next generation, functions in asymmetric or symmetric meiosis across unicellular and multicellular organisms. In asymmetric meiosis, meiotic drivers act to alter a chromosome's spatial position in a single egg. In symmetric meiosis, meiotic drivers cause phenotypic differences between gametes with and without the driver. Here we discuss existing models of meiotic drive, highlighting the underlying mechanisms and regulation governing systems for which the most is known. We focus on outstanding questions surrounding these examples and speculate on how new meiotic drive systems evolve and how to detect them.
Topics: Animals; Biological Evolution; Chromosome Segregation; Humans; Meiosis; Spindle Apparatus
PubMed: 33449147
DOI: 10.1007/s00018-020-03735-0 -
Journal of Advanced Research Sep 2023The R-loop is a naturally formed three-strand nucleic acid structure that recently has been reported to participate in multiple biological processes and helped answer...
INTRODUCTION
The R-loop is a naturally formed three-strand nucleic acid structure that recently has been reported to participate in multiple biological processes and helped answer some previously unexplained scientific questions. Meiosis process involves multiple chromatin-related events such as DNA double-stranded breaks (DSB) formation, repairing and transcriptional dynamics.
OBJECTIVES
Explore the regulatory roles and physiological functions of R-loops in the mammalian meiosis process.
METHODS
In our study, using genome-wide S9.6 CUT & Tag seq, we first mapped the genomic distribution and dynamic changes of R-loop during the meiotic process in mice, from spermatogonia to secondary spermatocytes. And we further explore the role of R-loop in physiological conditions by constructing conditional knockout mice of Rnaseh1, which deleted the R-loop endonuclease before meiosis entry.
RESULTS
R-loop predominantly distributes at promoter-related regions and varies across different meiotic stages. By joint analysis with the corresponding transcriptome, we found that the R-loop was closely related to transcription during the meiotic process. The high frequency of promoter-related R-loop in meiotic cells is usually accompanied by high transcription activity, and we further verified this in the leptotene/zygotene to the pachytene transition process. Moreover, the lack of RNase H1 caused sterility in male mice with R-loop accumulation and abnormal DSB repair in spermatocytes. Further analysis showed that abnormal R-loop accumulation in the leptotene/zygotene stages influenced transcriptional regulation in the pachytene stage.
CONCLUSION
The mutual regulation of the R-loop and transcription plays an essential role in spermatogenesis. And R-loop is also important for the normal repair process of DSB during meiosis.
Topics: Male; Mice; Animals; R-Loop Structures; DNA Breaks, Double-Stranded; Meiosis; Spermatogenesis; Spermatocytes; Mice, Knockout; Mammals
PubMed: 36396044
DOI: 10.1016/j.jare.2022.10.016