Blue-light-independent activity of Arabidopsis cryptochromes in the regulation of steady-state levels of protein and mRNA expression.
Cryptochromes are blue-light receptors that mediate blue-light inhibition of hypocotyl elongation and blue-light stimulation of floral initiation in Arabidopsis. In addition to their blue-light-dependent functions, cryptochromes are also involved in blue-light-independent regulation of the circadian clock, cotyledon unfolding, and hypocotyl inhibition. However, the molecular mechanism associated with the blue-light-independent function of cryptochromes remains unclear. We reported here a comparative proteomics study of the light regulation of protein expression. We showed that, as expected, the protein expression of many metabolic enzymes changed in response to both blue light and red light. Surprisingly, some light-regulated protein expression changes are impaired in the cry1cry2 mutant in both blue light and red light. This result suggests that, in addition to mediating blue-light-dependent regulation of protein expression, cryptochromes are also involved in the blue-light-independent regulation of gene expression. Consistent with this hypothesis, the cry1cry2 mutant exhibited reduced changes of mRNA expression in response to not only blue light, but also red light, although the cryptochrome effects on the red-light-dependent gene expression changes are generally less pronounced. These results support a hypothesis that, in addition to their blue-light-specific functions, cryptochromes also play roles in the control of gene expression mediated by the red/far-red-light receptor phytochromes.
Yang
Yue-Jun
YJ
Bioenergy and Biomaterial Research Center, Hunan University, Changsha 410082, China.
Zuo
Ze-Cheng
ZC
Zhao
Xiao-Ying
XY
Li
Xu
X
Klejnot
John
J
Li
Yan
Y
Chen
Ping
P
Liang
Song-Ping
SP
Yu
Xu-Hong
XH
Liu
Xuan-Ming
XM
Lin
Chen-Tao
CT
D017360:Arabidopsis / Q000235:genetics* / Q000378:metabolism* / Q000528:radiation effects; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism / Q000528:radiation effects; D002256:Carbonic Anhydrases / Q000235:genetics / Q000378:metabolism / Q000528:radiation effects; D056931:Cryptochromes / Q000235:genetics* / Q000378:metabolism* / Q000528:radiation effects; D004255:Deoxyribodipyrimidine Photo-Lyase / Q000235:genetics / Q000378:metabolism / Q000528:radiation effects; D018506:Gene Expression Regulation, Plant / Q000528:radiation effects*; D007700:Kinetics; D008027:Light; D016296:Mutagenesis; D009154:Mutation; D012333:RNA, Messenger / Q000235:genetics*; D018749:RNA, Plant / Q000235:genetics*; D036226:Seedlings / Q000235:genetics / Q000378:metabolism / Q000528:radiation effects; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
D029681:Arabidopsis Proteins; C538962:CRY1 protein, Arabidopsis; C103618:CRY2 protein, Arabidopsis; D056931:Cryptochromes; D012333:RNA, Messenger; D018749:RNA, Plant; D004255:Deoxyribodipyrimidine Photo-Lyase; D002256:Carbonic Anhydrases