Suja, J. A. | Search bioRxiv

bioRxiv2020

γ-H2AX is present at mouse meiotic kinetochores

The histone variant H2AX phosphorylated on serine 139, named {gamma}-H2AX, is a canonical DNA double-strand breaks marker. During mammalian meiotic prophase I, {gamma}-H2AX participates in meiotic recombination, meiotic sex chromosome inactivation and meiotic silencing of unsynapsed chromatin. In this study, we have analyzed the distribution of {gamma}-H2AX during male mouse meiosis by immunofluorescence on spread and squashed spermatocytes. We have found that {gamma}-H2AX locates at the inner kinetochore plate of meiotic kinetochores in both meiotic divisions. Therefore our results, for the first time, uncover a novel role for {gamma}-H2AX at mammalian meiotic kinetochores.

cell biology↗

bioRxiv2019

PDS5 proteins regulate the length of axial elements and telomere integrity during male mouse meiosis

Cohesin cofactors regulate the loading, maintenance and release of cohesin complexes from chromosomes during the mitotic cell cycle but little is known on their role during vertebrate meiosis. One such cofactor is PDS5, which exists in two versions in somatic and germline cells, PDS5A and PDS5B, with unclear functional specificity. Here we have analyzed their distribution and functions in mouse spermatocytes. We show that simultaneous elimination of PDS5A and PDS5B results in severe defects during prophase I while their individual depletion does not, suggesting a functional redundancy of the two factors. Shortened axial/lateral elements and a reduction of early recombination nodules are observed in the absence of both PDS5 proteins. Moreover, telomere integrity and their association to the nuclear envelope are severely compromised. As these defects occur without detectable reduction in chromosome-bound cohesin, we propose that the dynamic behavior of the complex, mediated by PDS5 proteins, is key for successful completion of meiotic prophase I.

cell biology↗