Abstract
Cryptochromes (CRYs) are the flavoproteins that have sequence similarities to the DNA photolyases. Although CRYs are conserved among eukaryotes and prokaryotes, it is suggested that they have emerged in parallel in various taxa. In plants, 'plant CRYs' function as blue-light photoreceptors, while 'bacterial CRYs' are suggested to be localized in the organelles, implying unknown mechanisms in the light signaling system mediated by CRYs.
The genome sequence of the acidothermophilic primitive red alga Cyanidioschyzon merolae was recently completed. It was showed that neither phytochrome genes nor phototropin genes were encoded in this genome, and that DNA photolyase/CRY genes were annotated, suggesting that C. merolae has light signaling pathways distinct from that of higher plants. We identified three plant CRYs and two bacterial CRYs and clarified their relationships through phylogenetic analyses. In addition, the expression analyses of these CRYs and the characterization of the recombinant CRY proteins will be reported.
