AI Article Synopsis
- * Key processes in prophase I include crossover formation and sister chromatid cohesion, which link homologous chromosomes and are essential for accurate chromosome segregation.
- * Errors in these processes can lead to missegregation of chromosomes, with increased risk as maternal age rises, potentially contributing to higher rates of aneuploidy in older oocytes.
Article Abstract
Formation of an oocyte involves a specialized cell division termed meiosis. In meiotic prophase I (the initial stage of meiosis), chromosomes undergo elaborate events to ensure the proper segregation of their chromosomes into gametes. These events include processes leading to the formation of a crossover that, along with sister chromatid cohesion, forms the physical link between homologous chromosomes. Crossovers are formed as an outcome of recombination. This process initiates with programmed double-strand breaks that are repaired through the use of homologous chromosomes as a repair template. The accurate repair to form crossovers takes place in the context of the synaptonemal complex, a protein complex that links homologous chromosomes in meiotic prophase I. To allow proper execution of meiotic prophase I events, signaling processes connect different steps in recombination and synapsis. The events occurring in meiotic prophase I are a prerequisite for proper chromosome segregation in the meiotic divisions. When these processes go awry, chromosomes missegregate. These meiotic errors are thought to increase with aging and may contribute to the increase in aneuploidy observed in advanced maternal age female oocytes.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1007/978-3-319-44820-6_5 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Diversification and recurrent adaptation of the synaptonemal complex in Drosophila.
PLoS Genet
January 2025
Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada.
The synaptonemal complex (SC) is a protein-rich structure essential for meiotic recombination and faithful chromosome segregation. Acting like a zipper to paired homologous chromosomes during early prophase I, the complex is a symmetrical structure where central elements are connected on two sides by the transverse filaments to the chromatin-anchoring lateral elements. Despite being found in most major eukaryotic taxa implying a deeply conserved evolutionary origin, several components of the complex exhibit unusually high rates of sequence turnover.
View Article and Find Full Text PDFArgonaute proteins are best known for their role in microRNA-mediated post-transcriptional gene silencing. Here, we show that AGO3 and AGO4, but not AGO2, localize to the sex chromatin of pachytene spermatocytes where they are required for transcriptional silencing of XY-linked genes, known as Meiotic Sex Chromosome Inactivation (MSCI). Using an mouse, we show that AGO3 and AGO4 are key regulators of spermatogenesis, orchestrating expression of meiosis-related genes during prophase I while maintaining silencing of spermiogenesis genes.
View Article and Find Full Text PDFGonadal sex and temperature independently influence germ cell differentiation and meiotic progression in .
Proc Natl Acad Sci U S A
January 2025
Department of Cell Biology, Duke University Medical Center, Durham, NC 27701.
In species with genetic sex determination (GSD), the sex identity of the soma determines germ cell fate. For example, in mice, XY germ cells that enter an ovary differentiate as oogonia, whereas XX germ cells that enter a testis initiate differentiation as spermatogonia. However, numerous species lack a GSD system and instead display temperature-dependent sex determination (TSD).
View Article and Find Full Text PDFDistinct and interdependent functions of three RING proteins regulate recombination during mammalian meiosis.
Proc Natl Acad Sci U S A
January 2025
HHMI, University of California, Davis, CA 95616.
During meiosis, each pair of homologous chromosomes becomes connected by at least one crossover, as required for accurate segregation, and adjacent crossovers are widely separated thereby limiting total numbers. In coarsening models, this crossover patterning results from nascent recombination sites competing to accrue a limiting pro-crossover RING-domain protein (COR) that diffuses between synapsed chromosomes. Here, we delineate the localization dynamics of three mammalian CORs in the mouse and determine their interdependencies.
View Article and Find Full Text PDFAn ultra-conserved poison exon in the Tra2b gene encoding a splicing activator is essential for male fertility and meiotic cell division.
EMBO J
January 2025
Newcastle University Biosciences Institute (NUBI), Central Parkway, Newcastle University, NE1 3BZ, Newcastle upon Tyne, UK.
The cellular concentrations of splicing factors (SFs) are critical for controlling alternative splicing. Most serine and arginine-enriched (SR) protein SFs regulate their own concentration via a homeostatic feedback mechanism that involves regulation of inclusion of non-coding 'poison exons' (PEs) that target transcripts for nonsense-mediated decay. The importance of SR protein PE splicing during animal development is largely unknown despite PE ultra-conservation across animal genomes.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!