Real-time analysis of the circadian oscillation of the Rev-Erbβ promoter

Aim: the rev-erbβ gene plays crucial roles in circadian rhythm,lipid and glucose metabolism,and several diseases. the molecular mechanisms of the transcriptional regulation of rev-erbβ that generate and determine the phase of the circadian oscillation remain unclear. methods: we analyzed the rev-erbβ promoter by luciferase reporter assays,real-time bioluminescence monitoring assays and electrophoretic mobility shift assays. results: luciferase reporter assays indicated that only the 5' region and exon 1 have obvious promoter activity. real-time bioluminescence monitoring assays revealed that e1,e2,e3,d boxes are important for maintenance of the amplitude of rev-erbβ oscillation. based on emsa results,rev-erbβ binds rores in the bmal1 promoter region and inhibits bmal1 promoter activity. conclusion: we provide direct evidence that three e-boxes and one d-box located in the first intron are crucial for the phase of circadian oscillation in rev-erbβ expression and that the sequences upstream from its transcription start site function as a promoter with no circadian regulation. we also found that the e1 box affects the rev-erbβ oscillation phase. our results offer new insight into the role of rev-erbβ in the circadian rhythm system.