Transcriptional regulation appears to be fundamental to circadian oscillations of clock gene expression. These oscillations are believed to control output rhythms. The transcriptional feedback loop and a model of interlocked loops have been proposed as the basis for these oscillations. We characterized the genomic structure of the @entity19 @entity14734 gene ( @entity14734 ) and defined the @entity14734 promoter region. Transcription of @entity14734 was activated by @entity26624 , @entity19344 , and @entity5394 , and was repressed by @entity8713 -CLOCK dimers. Therefore, CRY, @entity5394 , and @entity8713 -CLOCK play bidirectional roles in transcription when they are at high levels by late day and midnight, respectively. This underlies the opposite phase of @entity8713 compared to CRY and PER. We propose that a @entity8713 negative feedback loop interlocks with the CRY and @entity5394 negative feedback loop by inter-activation, forming a third positive forward loop. This transcriptional model suggests a molecular basis for the maintenance of stability, persistence, and period of circadian rhythms. The transcriptional potency of CRY is predominant within the @entity1 clock, suggesting a clearance mechanism for CRY in period maintenance. (c)2002 Elsevier Science (USA).

Interactivating feedback loops within the @entity1 clock: @entity8713 is negatively autoregulated and upregulated by @entity26624 , @entity19344 , and XXXX .

@entity5394 :: ('8864', 'Gene') :: ['PER2'] @entity19344 :: ('1408', 'Gene') :: ['CRY2'] @entity1 :: ('9606', 'Species') :: ['mammalian'] @entity26624 :: ('1407', 'Gene') :: ['CRY1'] @entity19 :: ('10090', 'Species') :: ['mouse'] @entity8713 :: ('406', 'Gene') :: ['BMAL1'] @entity14734 :: ('11865(Tax:10090)', 'Gene') :: ['Bmal1', 'mBmal1']
@entity5394 :: (8864,Gene) :: ['PER2']
