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Clock‐dependent and independent transcriptional control of the two isoforms from the mouse Rorγ gene
Author(s) -
Mongrain Valérie,
Ruan Xuan,
Dardente Hugues,
Fortier Erin E.,
Cermakian Nicolas
Publication year - 2008
Publication title -
genes to cells
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.912
H-Index - 115
eISSN - 1365-2443
pISSN - 1356-9597
DOI - 10.1111/j.1365-2443.2008.01237.x
Subject(s) - biology , gene isoform , gene expression , nuclear receptor , transcription factor , regulation of gene expression , gene , microbiology and biotechnology , genetics
Accumulating evidence indicate that molecular mechanisms generating circadian rhythms display some degree of tissue‐specificity. More specifically, distinct patterns of expression for nuclear receptors of the ROR family indicate that the transcriptional control of the clock gene Bmal1 differs among tissues. This study aims to investigate the expression of Rorγ isoforms ( Rorγ and Rorγt ) and characterize the molecular mechanisms underlying their tissue‐specific expression. The expression of Rorγ isoforms was assessed in mouse liver, muscle, thymus and testis throughout 24 h using quantitative RT‐PCR. Although the expression of Rorγ was rhythmic in the liver and thymus, it was constitutively expressed in muscle and testis. In contrast, the expression of Rorγt was constitutive in all four tissues. Furthermore, rhythmic expression of Rorγ was impaired in Clock mutant mice whereas the mutation had no effect on Rorγt expression. In line with these findings, luciferase assays revealed that transcription of the Rorγ promoter is clock‐controlled whereas that of Rorγt promoter is essentially clock‐independent. Our results provide insights into the molecular mechanisms that lead to differential expression of Rorγ and Rorγt and are suggestive of a framework that might account for tissue‐specific circadian regulation.