Phosphorylation of HORMA-domain protein HTP-3 at Serine 285 is dispensable for crossover formation
Authors
DAS, Debabrata, Shalini TRIVEDI (356 India, belonging to the institution), Jitka BLAŽÍČKOVÁ (203 Czech Republic, belonging to the institution), Swathi ARUR and Nicola SILVA (380 Italy, guarantor, belonging to the institution)
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.
Links
GA20-08819S, research and development project
Name: Pochopení úlohy PARG při podpoře tvorby a oprav dvouřetězcových zlomů DNA v meióze
Investor: Czech Science Foundation
LM2018129, research and development project
Name: Národní infrastruktura pro biologické a medicínské zobrazování Czech-BioImaging
Investor: Ministry of Education, Youth and Sports of the CR