Phosphorylation of HORMA-domain protein HTP-3 at Serine 285 is dispensable for crossover formation

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Authors

DAS Debabrata TRIVEDI Shalini BLAŽÍČKOVÁ Jitka ARUR Swathi SILVA Nicola

Year of publication 2022
Type Article in Periodical
Magazine / Source G3-Genes, Genomes, Genetics
MU Faculty or unit

Faculty of Medicine

Citation
Web https://academic.oup.com/g3journal/article/12/5/jkac079/6564663?login=true
Doi http://dx.doi.org/10.1093/g3journal/jkac079
Keywords Caenorhabditis elegans meiosis; HORMA-domain proteins; HTP-3
Description Generation of functional gametes is accomplished through a multilayered and finely orchestrated succession of events during meiotic progression. In the Caenorhabditis elegans germline, the HORMA-domain-containing protein HTP-3 plays pivotal roles for the establishment of chromosome axes and the efficient induction of programmed DNA double-strand breaks, both of which are crucial for crossover formation. Double-strand breaks allow for accurate chromosome segregation during the first meiotic division and therefore are an essential requirement for the production of healthy gametes. Phosphorylation-dependent regulation of HORMAD protein plays important roles in controlling meiotic chromosome behavior. Here, we document a phospho-site in HTP-3 at Serine 285 that is constitutively phosphorylated during meiotic prophase I. pHTP-3(S285) localization overlaps with panHTP-3 except in nuclei undergoing physiological apoptosis, in which pHTP-3 is absent. Surprisingly, we observed that phosphorylation of HTP-3 at S285 is independent of the canonical kinases that control meiotic progression in nematodes. During meiosis, the htp-3(S285A) mutant displays accelerated RAD-51 turnover, but no other meiotic abnormalities. Altogether, these data indicate that the Ser285 phosphorylation is independent of canonical meiotic protein kinases and does not regulate HTP-3-dependent meiotic processes. We propose a model wherein phosphorylation of HTP-3 occurs through noncanonical or redundant meiotic kinases and/or is likely redundant with additional phospho-sites for function in vivo.
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