Phosphoregulation of HORMA domain protein HIM-3 promotes asymmetric synaptonemal complex disassembly in meiotic prophase in < i > Caenorhabditis elegans < /i >

by Aya Sato-Carlton, Chihiro Nakamura-Tabuchi, Xuan Li, Hendrik Boog, Madison K. Lehmer, Scott C. Rosenberg, Consuelo Barroso, Enrique Martinez-Perez, Kevin D. Corbett, Peter Mark Carlton

In the two cell divisions of meiosis, diploid genomes are reduced into complementary haploid sets through the discrete, two-step removal of chromosome cohesion, a task carried out in most eukaryotes by protecting cohesion at the centromere until the second division. In eukaryotes without defined c entromeres, however, alternative strategies have been innovated. The best-understood of these is found in the nematodeCaenorhabditis elegans: after the single off-center crossover divides the chromosome into two segments, or arms, several chromosome-associated proteins or post-translational modifications become specifically partitioned to either the shorter or longer arm, where they promote the correct timing of cohesion loss through as-yet unknown mechanisms. Here, we investigate the meiotic axis HORMA-domain protein HIM-3 and show that it becomes phosphorylated at its C-terminus, within the conserved “closure motif” region bound by the related HORMA-domain proteins HTP-1 and HTP-2. Binding of HTP-2 is abrogated by phosphorylation of the closure motif inin vitro assays, strongly suggesting thatin vivo phosphorylation of HIM-3 likely modulates the hierarchical structure of the chromosome axis. Phosphorylation of HIM-3 only occurs on synapsed chromosomes, and similarly to other previously-descr...

Source: PLoS Genetics - November 11, 2020 Category: Genetics & Stem Cells Authors: Aya Sato-Carlton Source Type: research