It was first discovered inVaucheria frigida in 2007, by Takahashi et.al.Photosyntheticeukaryotes mainly convert sunlight into energy via photosynthesis, but light also is important for movement and development, regulation of biological activities. The effective wavelength for light responses in photosynthetic eukaryotes is mainly in the red light (RL) and blue light (BL) regions (Mohr 1980; Furuya 1993). The red/far-red receptorphytochrome and phytochrome-mediated responses like suppression ofhypocotyl growth have been studied intensively. BL-induced responses may includephototropism andchloroplast photo-relocation movement (Christie 2007). Various BL receptors have been discovered in green plants. Takahashi et.al isolated BL receptors from theXanthophyceae alga, Vaucheria in 2007 and named it Aureochrome (Latin meaning: aureus = gold). This new class of blue light photoreceptors is unique in a way because of the presence of abZIP (DNA binding domain) along with LOV (light perception) domain which makes it function astranscription factor as well as photoreceptor as shown by Takahashi et al. in 2007.
Fourorthologues of aureochromes have been identified in modeldiatomP. tricornutum, i.e. AUREO 1a, 1b, 1c and 2. Aureo1a recognizes the sequence TGACGT, which is the typical binding site for certain subfamilies of bZIP transcription factors. It was also shown that PtAUREO1a and 1c are regulated in a light-independentcircadian rhythm and that they are capable of forminghomodimers andheterodimers which recognize the ACGT core sequence within the aureochrome.[4] The photoreactions of AUREO 1 protein have been studied recently by Tsuguyoshi et al (2011) and they concluded that the AUREO1-LOV exists in equilibrium between themonomer anddimer. Huysman et al. showed that Aureo1a is involved in regulation of expression of diatom-specific cyclin dsCYC2 which is involved in G1 to S phase transition after dark arrest in 2013. Aureo1a, indeed is shown to function as a repressor of high lightacclimation.[5][6]
^Madhuri, S.; Río Bártulos, C.; Serif, M.; Lepetit, B.; Kroth, P.G. (2019). "A strategy to complement PtAUREO1a in TALEN knockout strains of Phaeodactylum tricornutum".Algal Research.39: 101469.doi:10.1016/j.algal.2019.101469.
