Molecular Cloning and Expression Analysis of the Cryptochrome Gene in Antarctic Ice Alga sp. ICE-L.

Cryptochrome (CRY) is a kind of flavin-binding protein that can sense blue light and near-ultraviolet light, and participates in the light response of organisms and the regulation of the circadian clock. The complete open reading frame (ORF) of (GenBank ID OM389130.1), encoding one kind of CRY, was cloned from the Antarctic ice alga sp. ICE-L. The quantitative real-time PCR study showed that the expression level of the gene was the highest at 5 °C and salinity of 32‱. was positively regulated by blue or yellow light, suggesting that it is involved in the establishment of photomorphology. The gene can respond to polar day and polar night, indicating its expression is regulated by circadian rhythm. The expression level of was most affected by UVB irradiation, which may be related to the adaptation of ice algae to a strong ultraviolet radiation environment. Moreover, the recombinant protein of was expressed by prokaryotic expression. This study may be important for exploring the light-induced rhythm regulation of Antarctic ice algae in the polar marine environment.