CSL encodes a leucine-rich-repeat protein implicated in red/violet light signaling to the circadian clock in Chlamydomonas.
The green alga Chlamydomonas reinhardtii shows various light responses in behavior and physiology. One such photoresponse is the circadian clock, which can be reset by external light signals to entrain its oscillation to daily environmental cycles. In a previous report, we suggested that a light-induced degradation of the clock protein ROC15 is a trigger to reset the circadian clock in Chlamydomonas. However, light signaling pathways of this process remained unclear. Here, we screened for mutants that show abnormal ROC15 diurnal rhythms, including the light-induced protein degradation at dawn, using a luciferase fusion reporter. In one mutant, ROC15 degradation and phase resetting of the circadian clock by light were impaired. Interestingly, the impairments were observed in response to red and violet light, but not to blue light. We revealed that an uncharacterized gene encoding a protein similar to RAS-signaling-related leucine-rich repeat (LRR) proteins is responsible for the mutant phenotypes. Our results indicate that a previously uncharacterized red/violet light signaling pathway is involved in the phase resetting of circadian clock in Chlamydomonas.
Center for Gene Research, Nagoya University, Nagoya, Japan.|Graduate School of Science, Nagoya University, Nagoya, Japan.
Ayumi
A
Kinoshita
Center for Gene Research, Nagoya University, Nagoya, Japan.|Graduate School of Science, Nagoya University, Nagoya, Japan.
Yoshimi
Y
Niwa
Center for Gene Research, Nagoya University, Nagoya, Japan.
Kiyoshi
K
Onai
Graduate School of Biostudies, Kyoto University, Kyoto, Japan.
Takashi
0000-0001-6578-8095
T
Yamano
Graduate School of Biostudies, Kyoto University, Kyoto, Japan.
Hideya
H
Fukuzawa
Center for Gene Research, Nagoya University, Nagoya, Japan.|Graduate School of Science, Nagoya University, Nagoya, Japan.
Masahiro
M
Ishiura
Center for Gene Research, Nagoya University, Nagoya, Japan.|Graduate School of Science, Nagoya University, Nagoya, Japan.
Takuya
0000-0002-8030-2361
T
Matsuo
D020418:Algal Proteins / Q000235:genetics* / Q000378:metabolism; D015153:Blotting, Western; D016825:Chlamydomonas reinhardtii / Q000235:genetics / Q000378:metabolism / Q000528:radiation effects*; D057906:Circadian Clocks / Q000235:genetics*; D002940:Circadian Rhythm / Q000235:genetics / Q000528:radiation effects; D003593:Cytoplasm / Q000235:genetics / Q000378:metabolism; D015870:Gene Expression / Q000528:radiation effects; D007150:Immunohistochemistry; D000090263:Leucine-Rich Repeat Proteins; D008027:Light; D009154:Mutation; D010766:Phosphorylation / Q000528:radiation effects; D011506:Proteins / Q000235:genetics* / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction / Q000235:genetics / Q000528:radiation effects
D020418:Algal Proteins; D000090263:Leucine-Rich Repeat Proteins; D011506:Proteins; D012333:RNA, Messenger