title: Nuclear receptor-mediated cell-autonomous oscillatory expression of the circadian transcription factor, neuronal PAS domain protein 2 (NPAS2).
abstract: NPAS2 (MOP4) is a heme-containing sensor transcription factor responsive to a wide range of intra- and extracellular stimuli, which also functions as a circadian transcription factor. This molecule forms a heterodimer with another circadian transcription factor, BMAL1, and activates transcription via E-box elements, indicating that circadian phase synchronization between NPAS2 and BMAL1 expression is important for the efficient transcriptional activation of target genes. However, details of the mechanism of cell-autonomous circadian transcription of Npas2 remain unclear. Here, we show that one of the ROREs (retinoid-related orphan receptor response elements) in the upstream region of the transcription start site is essential for circadian transcription of the Npas2 gene. Furthermore, we also show that endogenous RORα indeed plays an essential role in cell-autonomous circadian transcription of Npas2, because a damped transcriptional oscillation was observed not only by introduction of a dominant negative form or small interfering RNA but also in embryonic fibroblasts obtained from RORα-mutant (sg/sg) mice. These results indicate that circadian transcription of Npas2 is synchronized with that of Bmal1 in a cell-autonomous nuclear receptor-mediated fashion.
authors.affiliation: From the The Research Institute for Time Studies, Yamaguchi University, 1677-1 Yoshida, Yamaguchi 753-8511, Japan.
authors.forename: Ritsuko
authors.initials: R
authors.lastname: Matsumura
authors.forename: Chiaki
authors.initials: C
authors.lastname: Matsubara
authors.forename: Koichi
authors.initials: K
authors.lastname: Node
authors.forename: Toru
authors.initials: T
authors.lastname: Takumi
authors.forename: Makoto
authors.initials: M
authors.lastname: Akashi
mesh_terms: D056930:ARNTL Transcription Factors / Q000235:genetics / Q000378:metabolism; D000818:Animals; D051792:Basic Helix-Loop-Helix Proteins / Q000235:genetics* / Q000378:metabolism; D002940:Circadian Rhythm / Q000235:genetics*; D005347:Fibroblasts / Q000378:metabolism; D006801:Humans; D051379:Mice; D009154:Mutation; D041681:NIH 3T3 Cells; D009419:Nerve Tissue Proteins / Q000235:genetics* / Q000378:metabolism; D057094:Nuclear Receptor Subfamily 1, Group F, Member 1 / Q000235:genetics / Q000378:metabolism*; D020218:Response Elements; D024363:Transcription Initiation Site; D014158:Transcription, Genetic
chemical_list: D056930:ARNTL Transcription Factors; D051792:Basic Helix-Loop-Helix Proteins; D009419:Nerve Tissue Proteins; D057094:Nuclear Receptor Subfamily 1, Group F, Member 1; C538961:Bmal1 protein, mouse; C104264:NPAS2 protein, human; C539738:RORA protein, human
keywords: Circadian Clock; Circadian Rhythms; Clock Genes; Nuclear Receptors; Transcription; Transcription Factors