Regulation of < i > ddb2 < /i > expression in blind cavefish and zebrafish reveals plasticity in the control of sunlight-induced DNA damage repair

by Haiyu Zhao, Hongxiang Li, Juan Du, Giuseppe Di Mauro, Sebastian Lungu-Mitea, Nathalie Geyer, Daniela Vallone, Cristiano Bertolucci, Nicholas S. Foulkes We have gained considerable insight into the mechanisms which recognize and repair DNA damage, but how they adapt to extreme environmental challenges remains poorly understood. Cavefish have proven to be fascinating models for exploring the evolution of DNA repair in the complete absence of UV-ind uced DNA damage and light. We have previously revealed that the Somalian cavefishPhreatichthys andruzzii, lacks photoreactivation repair via the loss of light, UV and ROS-inducedphotolyase gene transcription mediated by D-box enhancer elements. Here, we explore whether other systems repairing UV-induced DNA damage have been similarly affected in this cavefish model. By performing a comparative study usingP.andruzzii and the surface-dwelling zebrafish, we provide evidence for a conservation of sunlight-regulated Nucleotide Excision Repair (NER). Specifically, the expression of theddb2 gene which encodes a key NER recognition factor is robustly induced following exposure to light, UV and oxidative stress in both species. As in the case of thephotolyase genes, D-boxes in theddb2 promoter are sufficient to induce transcription in zebrafish. Interestingly, despite the loss of D-box-regulated photolyase gene expression inP.andruzzii, the D-box is required forddb2 induction by visible light and oxidative stress in cavefish. However, in ...
Source: PLoS Genetics - Category: Genetics & Stem Cells Authors: Source Type: research