Narya, a RING finger domain-containing protein, is required for meiotic DNA double-strand break formation and crossover maturation in Drosophila melanogaster

Abstract

Meiotic recombination, which is necessary to ensure that homologous chromosomes segregate properly, begins with the induction of meiotic DNA double-strand breaks (DSBs) and ends with the repair of a subset of those breaks into crossovers. Here we investigate the roles of two paralogous genes, CG12200 and CG31053, which we have named Narya and Nenya, respectively, due to their relationship with a structurally similar protein named Vilya. We find that narya recently evolved from nenya by a gene duplication event, and we show that these two RING finger domain-containing proteins are functionally redundant with respect to a critical role in DSB formation. Narya colocalizes with Vilya foci, which are known to define recombination nodules, or sites of crossover formation. A separation-of-function allele of narya retains the capacity for DSB formation but cannot mature those DSBs into crossovers. We further provide data on the physical interaction of Narya, Nenya and Vilya, as assayed by the yeast two-hybrid system. Together these data support the view that all three RING finger domain-containing proteins function in the formation of meiotic DNA DSBs and in the process of crossing over.

Coupling DNA Damage and Repair: an Essential Safeguard during Programmed DNA Double-Strand Breaks?

“…Interestingly, a separation-of-function allele of Narya, in its RING finger domain, shows that Narya is not only involved in DSB formation, but also required for their repair as a crossover. In addition, the three proteins show two sequential localization patterns; first, early with DSB sites and then, to crossover sites [75,76]. This illustrates again a double function for meiotic DSB formation and their repair into crossovers within a single protein, therefore directly coupling these two steps of meiotic recombination.…”

“…Another example of coupling between meiotic DSB formation and repair comes from the fruit fly Drosophila, where a protein, Narya, fulfills functions both for formation and repair of meiotic DSBs with a crossing over, to ensure proper homolog segregation and successful meiosis [75]. Narya is a RING finger protein that is redundant with another related protein, Nanya, for meiotic DSB formation and repair.…”

The E3 ubiquitin ligase Sina regulates the assembly and disassembly of the synaptonemal complex in Drosophila females

“…As is the case for centromeres, the recombination machinery may be able to recognize the polycomplexes as SC to affect the localization of DSBs. In Drosophila females the Vilya and Narya proteins, which are required for DSB formation and repair, initially localize to the central region of the SC, as well as to DSBs [66,67]. It is possible these and other DSB associated proteins are mediating the localization of DSBs near sina polycomplexes.…”

“…To measure only X chromosome nondisjunction in S1B Fig and meiotic recombination along the X chromosome, virgin females (one virgin per vial for wild type, two for sina A4 and three for sina A4 /sina Df due to decreased fertility) were mated to y sc cv v f/B S Y males. For a description of the calculations of adjusted total progeny and X nondisjunction, see [66]. For recombination of the X chromosome in Table 5, genotypes were y sc cv v f y+/y w (wild type), y sc cv v f y+/y; sina A4 , and y sc cv v f y+/y w; sina A4 /sina Df .…”

Robust designation of meiotic crossover sites by CDK-2 through phosphorylation of the MutSγ complex

“…Throughout eukaryotes, crossover recombination is primarily controlled by a group of proteins collectively termed “ZMM” (Pyatnitskaya et al, 2019). Notably, homologs of the yeast Ring domain protein Zip3 (ZHP-1, -2, -3, and -4 in C. elegans (Bhalla et al, 2008; Jantsch et al, 2004; Nguyen et al, 2018; Zhang et al, 2018), Drosophila Vilya and Narya/Nenya (Lake et al, 2019; Lake et al, 2015), Hei10 in Arabidopsis (Chelysheva et al, 2012), and Hei10 and RNF212 in mammals (Reynolds et al, 2013; Ward et al, 2007)) initially localize as abundant foci or long stretches along the synaptonemal complex (SC) but eventually concentrate at crossover sites in late pachytene (Agarwal and Roeder, 2000). These SUMO or ubiquitin ligases appear to promote crossover designation by stabilizing the ZMM proteins at crossover sites while removing them from other recombination intermediates (Nguyen et al, 2018; Qiao et al, 2014; Rao et al, 2017; Reynolds et al, 2013; Ward et al, 2007; Zhang et al, 2018).…”