Dynamic configurations of meiotic DNA-break hotspot determinant proteins

Abstract

Appropriate DNA double-strand-break (DSB) and crossover distributions are required for proper meiotic chromosome segregation. Schizosaccharomyces pombe linear element proteins (LinEs) determine DSB hotspots; LinE-bound hotspots form 3D clusters over ∼200 kb chromosomal regions. Here, we investigated LinE configurations and distributions in live cells using super-resolution fluorescence microscopy. We found LinEs form two chromosomal structures, dot-like and linear structures, in both zygotic and azygotic meiosis. Dot-like LinE structures appeared around the time of meiotic DNA replication, underwent dotty-to-linear-to-dotty configurational transitions, and disassembled before the first meiotic division. DSB formation and repair did not detectably influence LinE structure formation, but failure of DSB formation delayed disassembly. Recombination-deficient LinE missense mutants formed dot-like but not linear LinE structures. Our quantitative study reveals a transient form of LinE structures and suggests a novel role for LinE proteins in regulating meiotic events, such as DSB repair. We discuss the relation of LinEs and the synaptonemal complex in other species.

Cyclins and CDKs in the regulation of meiosis-specific events

“…Interestingly, CDK downregulation impairs the chromatin binding of Rec25, a structural component of the Lin ear E lements (LinEs). LinEs are chromosome axis structures with similarity to the SC axial/lateral elements of other eukaryotes ( Lorenz et al, 2004 ; Davis et al, 2008 ; Ding et al, 2021 ; Chuang and Smith, 2022 ). They are required for DSB formation and preferentially enriched at recombination hotspots ; furthermore, when misplaced they induce DSBs ( Fowler et al, 2013 ; Martin-Castellanos et al, 2013 ; Nambiar and Smith, 2018 ).…”