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 these cells employ a number of known 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 highly conserved regulator of genome stability in flies, worms, zebrafish, and humans. GCNA contains a long 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, most 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.

GCNA preserves genome integrity and fertility across species