GCNA: Guardian of the Genome

Abstract

The propagation of species depends on the ability of germ cells to protect their genome in the face of numerous exogenous and endogenous threats. While germ cells employ a number of know repair pathways, specialized mechanisms that ensure high-fidelity replication, chromosome segregation, and repair of germ cell genomes remain incompletely understood. Here, we identify Germ cell nuclear acidic peptidase (GCNA) as a conserved regulator of genome stability in flies, worms, zebrafish and human germ cell tumors. GCNA contains an acidic intrinsically disordered region (IDR) and a protease-like SprT domain. In addition to chromosomal instability and replication stress, Gcna mutants accumulate DNA-protein crosslinks (DPCs). GCNA acts in parallel with a second SprT domain protein Spartan. Structural analysis reveals that while the SprT domain is needed to limit meiotic and replicative damage, much of GCNA's function maps to its IDR. This work shows GCNA protects germ cells from various sources of damage, providing novel insights into conserved mechanisms that promote genome integrity across generations.