مشخصات پژوهش

Volvocine lineage, categorized in the Chlorophyta phylum, includes multicellular algae (such as Volvox) and the single-celled Chlamydomonas. After genome sequencing and annotation of V. carteri, some predicted photoreceptor coding genes were discovered in its genome. These genes create a sophisticated light-sensing system to adjust the physiology, growth, development, and behavior of the green alga. The specific light-sensitive modules are used to engineer the optogenetic tools as photo-switchable instruments. Given this, the current study presents a description of two nuclear photolyase/cryptochrome gene loci (VcCPF5 and VcCPF8) in V. carteri. In this regard, we conducted in-silico and experimental analyses to investigate the protein functions. Phylogenetic analysis revealed that these genes encode two proteins related to DASH-cryptochrome subclade. In addition, the 3D model of these proteins showed their similarity with photolyase protein family members with DNA repair activity. Furthermore, VcCPF5 and VcCPF8 transcripts increased after red and blue-light treatments during the gonidia maturation phase of microalga which were confirmed by determining the light responsive elements in their putative promoters. Moreover, based on the spectrophotometric analysis of purified and un-purified proteins, they had absorption in the blue-light spectrum like the other members of the cryptochrome/photolyase protein family. Additionally, the transgenic Escherichia coli containing the heterologous tagged proteins were found which increase the survival capability under UV-irradiation compared to the control samples. In conclusion, our findings demonstrated that the expression of DASH-related genes in Volvox rely on the light quality. Moreover, in- vivo and in-silico studies confirmed that these proteins are involved in the light dependent DNA repair process. Then they can be suggested as potential candidates for designing Light-Inducible DNA-Repair (LIDR) tools in the optogenetics