Circadian phosphorylation of ATF-2, a potential activator of Period2 gene transcription in the chick pineal gland.
Stimulus-induced transcription of the Period gene is a critical step for phase-shift of vertebrate circadian systems. The promoter region of chicken Period2 contains a canonical calcium/cAMP-responsive element, but its functional relevance is not known. The present study shows that cAMP-responsive element-binding protein (CREB) and activating transcription factor-2 (ATF-2) bind to the promoter region of the Period2 gene in the chick pineal gland. In transient transfection assays, a reporter construct containing 0.7-kbp upstream region of chicken Period2 was transactivated by ATF-2, but it was poorly responsive to CREB. In the chick pineal gland, phosphorylation of CREB protein at the kinase-inducible domain was negatively regulated by light. On the other hand, phosphorylation of ATF-2 at the amino-terminal transactivation domain exhibited a circadian rhythm with a daytime peak, suggesting a role for ATF-2 in circadian rhythmicity in the chick pineal gland.
Shimizu
Fumiko
F
Department of Biophysics and Biochemistry, Graduate School of Science, The University of Tokyo, Bunkyo-Ku, Tokyo, Japan.
Fukada
Yoshitaka
Y
D051696:Activating Transcription Factors / Q000378:metabolism*; D000818:Animals; D000831:Animals, Newborn; D001798:Blood Proteins / Q000378:metabolism*; D002645:Chickens; D047369:Chromatin Immunoprecipitation / Q000379:methods; D002940:Circadian Rhythm / Q000502:physiology*; D017362:Cyclic AMP Response Element-Binding Protein / Q000378:metabolism; D008156:Luciferases; D008954:Models, Biological; D009687:Nuclear Proteins / Q000378:metabolism; D009924:Organ Culture Techniques; D010766:Phosphorylation; D010870:Pineal Gland / Q000502:physiology*; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D014158:Transcription, Genetic
D051696:Activating Transcription Factors; D001798:Blood Proteins; D017362:Cyclic AMP Response Element-Binding Protein; D009687:Nuclear Proteins; D008156:Luciferases