RNF212B E3 ligase is essential for crossover designation and maturation during male and female meiosis in the mouse

ABSTRACT: Meiosis, a reductional cell division, relies on precise initiation, maturation and resolution of crossovers (COs) during prophase I to ensure the accurate segregation of homologous chromosomes during metaphase I. This process is regulated by the interplay of RING-E3 ligases such as RNF212 and HEI10 in mammals. In this study, we characterized a novel RNF212B E3 ligase. RNF212B colocalizes and interacts with RNF212 forming small foci along chromosome cores from zygonema onwards. These consolidate into larger foci at maturing COs, colocalizing with HEI10, CNTD1, and MLH1 at pachynema in a synapsis-dependent and DSB-independent manner. Genetically, RNF212B focus formation depends on Rnf212 but not on Msh4, Hei10 and Cntd1, while the unloading of RNF212B at the end of pachynema is dependent on Hei10 and Cntd1. Rnf212b-deficient and enzymatically-dead mutant mice exhibit modest synapsis defects, a reduction in localization of pro-CO factors (MSH4, TEX11, RPA, MZIP2) and absence of MLH1, indicative of nascent COs, resulting in metaphase I with mostly univalent chromosomes. Double mutants for Rnf212b and Rnf212 exhibit an identical phenotype to that of Rnf212b single mutants, while double heterozygous demonstrate a dosage-dependent reduction in the number of COs relative to the single mutant, indicating a functional interplay between both paralogs. SUMOylome analysis of testes from Rnf212b mutants and pull-down analysis of Sumo- and Ubiquitin-tagged HeLa cells, suggest that RNF212B is a novel E3-ligase with Ubiquitin activity, serving as a crucial factor for CO designation and maturation. This conserved pathway holds physiological significance for understanding the biology and homeostasis of COs.

INSTRUMENT(S): Orbitrap Fusion Lumos

ORGANISM(S): Homo Sapiens (human)

TISSUE(S): Cell Culture

SUBMITTER: Román González-Prieto  

LAB HEAD: Román González Prieto

PROVIDER: PXD050239 | Pride | 2024-05-31

REPOSITORIES: pride