Substitution of a Conserved Glycine in the PHR Domain of Arabidopsis CRYPTOCHROME 1 Confers a Constitutive Light Response

• Published in: Molecular plant 2012, Vol.5 (1), p.85-97
• Main Authors: Gu, Nan-Nan, Zhang, Yan-Chun, Yang, Hong-Quan
• Format: Article
• Language: English
• Subjects: Amino Acid Motifs; Amino Acid Substitution; Arabidopsis; Arabidopsis - chemistry; Arabidopsis - genetics; Arabidopsis - metabolism; Arabidopsis - radiation effects; Arabidopsis Proteins - chemistry; Arabidopsis Proteins - genetics; Arabidopsis Proteins - metabolism; Conserved Sequence; COP phenotype; COP1; CRY1; CRY1 G380R; Cryptochromes - chemistry; Cryptochromes - genetics; Cryptochromes - metabolism; Gene Expression Regulation, Plant - radiation effects; Genotype & phenotype; Glycine - genetics; Glycine - metabolism; Light; Protein Structure, Tertiary; Proteins; 信令机制; 光响应; 取代甘氨酸; 守恒; 拟南芥; 转基因植物; 过度表达
• ISSN: 1674-2052; 1752-9867
• DOI: 10.1093/mp/ssr052

CRYPTOCHROMES （CRYs） are photolyase-like ultraviolet-A/blue light photoreceptors that mediate various light responses in plants. The signaling mechanism of Arabidopsis CRYs （CRY1 and CRY2） involves direct CRY-COP1 interaction. Here, we report that CRY1G380R, which carries a Gly-to-Arg substitution of the highly conserved G380 in the photo-lyase-related （PHR） domain of Arabidopsis CRY1, shows constitutive CRY1 photoreceptor activity in Arabidopsis. Transgenic plants overexpressing CRY1G380R display a constitutively photomorphogenic （COP） phenotype in darkness, as well as a dramatic early flowering phenotype under short-day light conditions （SD）. We further demonstrate that CRY1G380R expression driven by the native CRY1 promoter also results in a COP phenotype in darkness. Moreover, over- expression of either the Arabidopsis homolog CRY2G377R or the rice ortholog OsCRYlbG388R of CRY1G380R in Arabidopsis results in a COP phenotype in darkness. Cellular localization studies indicate that CRY1G380R co-localizes with COP1 in the same nuclear bodies （NBs） in vivo and inhibits the nuclear accumulation of COP1 in darkness. These results suggest that the conserved G380 may play a critical role in regulating the photoreceptor activity of plant CRYs and that CRY1G380R might constitutively phenocopy the photo-activated CRY1 in darkness and thus constitutively mediate CRY1 signaling.