In this organism, the nucleus elongates and moves back and forth between the cell ends during meiotic prophase while telomeres remain clustered at the leading edge of the moving nucleus (Chikashige et al. The fission yeast Schizosaccharomyces pombe exhibits a striking example of the bouquet arrangement. It has been suggested that a “bouquet” arrangement of chromosomes, in which chromosomes are bundled at the telomeres to form a polarized configuration, contributes to the pairing of homologous chromosomes by spatially aligning them (Zickler and Kleckner 1998 Scherthan 2001 Chikashige et al. 2012).ĭuring the pairing process, each homologous pair of chromosomes is selectively aligned. Understanding the mechanisms involved in the pairing and recombination of homologous chromosomes is clinically important because chromosome missegregation during meiosis is a major cause of human miscarriage and developmental abnormalities (Nagaoka et al. During this process, the pairing of homologous chromosomes results in recombination-mediated physical links between them that are essential for the correct segregation of meiotic chromosomes. Meiosis is an important process for sexually reproducing eukaryotic organisms, generating inheritable haploid gametes from a parental diploid cell. Thus, Rec8 and Pds5 play an essential role in building a platform to support the chromosome architecture necessary for the spatial alignment of homologous chromosomes. In rec8 or pds5 mutants, the frequency of homologous chromosome pairing is reduced. In the absence of Pds5, the Rec8 axis is shortened whereas chromosomes are widened. In this study, using super-resolution structured illumination microscopy, we found that Rec8 forms a linear axis on chromosomes, which is required for the organized axial structure of chromatin during meiotic prophase. These studies revealed that chromosomes are elongated in the absence of the meiotic cohesin subunit Rec8 and shortened in the absence of the cohesin-associated protein Pds5. We previously demonstrated that the meiotic cohesin complex is required for chromosome compaction during meiotic prophase in the fission yeast Schizosaccharomyces pombe. An early meiotic event involves the replacement of the non-SMC mitotic cohesins with their meiotic equivalents in most part of the chromosome, forming an axis on meiotic chromosomes. Chromosome structure is dramatically altered upon entering meiosis to establish chromosomal architectures necessary for the successful progression of meiosis-specific events.
0 Comments
Leave a Reply. |
Details
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |