dUTPase is essential in zebrafish development and possesses several single-nucleotide variants with pronounced structural and functional consequences.

Genome stability and faithful DNA replication are essential for cell viability. Numerous interlinked pathways in DNA damage recognition, repair and maintenance of physiologically competent nucleotide pools contribute to providing a solid framework to uphold DNA integrity. The enzyme family of dUTPases is involved in balancing the appropriate nucleotide pools by removing dUTP from the cellular milieu and providing dUMP for thymidylate de novo biosynthesis. In the present study, we show that dUTPase is essential for normal development in zebrafish. We also found that the fish dut gene from different genomes contains several single-nucleotide variations (SNPs). This observation prompted structural and functional investigations of the SNP variants at the protein level. Results indicated that none of the mutation sites of the variants are within the active site. Still, one of the variants showed drastically lower protein stability and catalytic efficiency as compared to the other two dUTPase variants, underlining the importance of detailed characterization of SNPs even at sites distant from the active site. In conclusion, we demonstrate the importance of dUTPase function in zebrafish development and unveil the role of several point mutations on protein structure and function.