CLOCK:BMAL-independent circadian oscillation of zebrafish Cryptochrome1a gene.
In the vertebrate circadian feedback loop, CLOCK:BMAL heterodimers induce the expression of Cry genes. The CRY proteins in turn inhibit CLOCK:BMAL-mediated transcription closing the negative feedback loop. Four CRYs, which all inhibit CLOCK:BMAL-mediated transcription, exist in zebrafish. Although these zebrafish Crys (zCry1a, 1b, 2a, and 2b) show a circadian pattern of expression, previous studies have indicated that the circadian oscillation of zCry1a could be CLOCK:BMAL-independent. Here we show that abrogation of CLOCK:BMAL-dependent transcription in zebrafish cells by the dominant negative zCLOCK3-DeltaC does not affect the circadian oscillation of zCry1a. Moreover, we provide several lines of evidence indicating that the extracellular signal-regulated kinase (ERK) signaling cascade modulates the circadian expression of zCry1a gene in constant darkness. Taken together, our data strongly support the notion that circadian oscillation of zCry1a is CLOCK:BMAL-independent and further indicate that mechanisms involving non-canonical clock genes could contribute to the circadian expression of zCry1a gene in a cell autonomous manner.
Miyamura
Norio
N
Department of Developmental and Regenerative Biology, Tokyo Medical and Dental University.
Hirayama
Jun
J
Sawanobori
Kenji
K
Tamaru
Teruya
T
Asaoka
Yoichi
Y
Honda
Reiko
R
Yamamoto
Takuro
T
Uno
Hatsume
H
Takamatsu
Ken
K
Nishina
Hiroshi
H
D056930:ARNTL Transcription Factors; D000818:Animals; D051792:Basic Helix-Loop-Helix Proteins / Q000235:genetics / Q000378:metabolism*; D015153:Blotting, Western; D056926:CLOCK Proteins; D002478:Cells, Cultured; D002940:Circadian Rhythm / Q000235:genetics* / Q000502:physiology; D008027:Light; D055503:Protein Multimerization; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic; D015027:Zebrafish / Q000235:genetics* / Q000502:physiology; D029961:Zebrafish Proteins / Q000235:genetics*
D056930:ARNTL Transcription Factors; D051792:Basic Helix-Loop-Helix Proteins; D056926:CLOCK Proteins; D015534:Trans-Activators; D029961:Zebrafish Proteins