Abstract
We discovered two novel flavoproteins in the coenocytic alga, Vaucheria frigida (Xanthophyceae, Heterokontophyta, Stramenopile). They have each one bZIP- and one LOV domain. They are probably photoreceptors for the blue light-induced branching, a photo(cyto)morphogenesis, as the response is completely inhibited when their mRNAs are knocked out by RNA interference (PCP meeting at Niigata 2005). One of these bZIP-LOV proteins is suggested to be involved in the sex-organ development. We found several orthologs in mRNA of Fucus distichus (Phaeophyta) and in the genome of the marine diatom, Thalassiosira pseudonana (Ambrust et al. 2004). We thus name the bZIP-LOV photoreceptor AUREOCHROME. AUREOCHROME seems to be the common and intrinsic blue light photoreceptor of Stramenopile. Instead, no PHOTOTROPIN has been found in Stramenopiles, We are intending to isolate AUREOCHROMEs from other members of the Stramenopiles and the related algal groups whose chloroplasts are red algal symbiotic origin, such as Haptophytes and Cryptophytes.
