Relative Base Excision Repair in Xiphophorus Fish Tissue Extracts

Abstract:

To begin characterizing DNA repair capability among Xiphophorus species, we adapted oligonucleotide-based DNA repair assays to extracts of fish tissues. Here, we report the initial results of relative base excision repair (BER) capability among 3 inbred Xiphophorus fish lines representing 2 species (X. maculatus and X. couchianus), and interspecies hybrid F₁ animals produced by crossing them. Overall, data from uracil-N-glycosylase (UNG)–initiated BER assay (UNG-BER) indicate that brain tissue extracts generally possess higher BER activity than do gill and liver extracts. UNG-BER activities in gill and liver extracts were similar. The BER activity in the tissues of F₁ interspecies hybrids followed the activity pattern of the X. couchianus parent in gill and liver extracts, was similar to the X. maculatus parent in brain extracts, but exhibited a reduced repair capacity in gill tissue extracts compared with either parent. We discuss the use of oligonucleotide-based DNA repair assays to elucidate the role that inheritance of DNA repair potential may play in susceptibility to disease and tumorigenesis in the intact organism.