DNA double-strand breaks (DSBs) are repaired throughout three major pathways that require a specific set of proteins: Non-Homologous End-Joining (NHEJ), Microhomology-Mediated End-Joining (MMEJ), and Homology-Directed Repair (HDR). Such pathways and their proteins have been studied in model organisms, including the fruit fly. Nevertheless, little is known about the DNA repair pathways of DSBs in Crustacea and much less in the penaeids shrimps (Crustacea: Decapoda: Penaeidae). From the joining of oligonucleotides and midgut gland (hepatopancreas) extracts, it has been shown that HDR and MMEJ but not NHEJ occur in Penaeus monodon (Penaeidae).
To know if the NHEJ pathway could come about in Penaeus vannamei , we searched the NHEJ-related proteins in transcriptome and proteome databases of P. vannamei and other Decapoda species. Expression of NHEJ-related proteins Ku70, Ku80, DNA-PKcs, and DNA ligase 4 (as well as HDR- and MMEJ-related proteins) was assessed in P. vannamei gills, midgut gland, hemocytes, and muscle throughout semi-quantitative RT-PCR. DSB repair proteins were found to be expressed in the four tissues, particularly in the gills and midgut gland. Among DSB repair proteins, those related to NHEJ pathway were the most abundant in gills. As far as we know, this is the first report on DSB repair proteins for a decapod. Together, proteomic, transcriptomic, and expression data suggest that the NHEJ pathway occurs in P. vannamei and other decapods. The information presented here is relevant for ecotoxicology studies and the designing of gene edition strategies, which have not been developed in P. vannamei.