Redundant function of REV-ERBalpha and beta and non-essential role for Bmal1 cycling in transcriptional regulation of intracellular circadian rhythms.

The mammalian circadian clockwork is composed of a core PER/CRY feedback loop and additional interlocking loops. In particular, the ROR/REV/Bmal1 loop, consisting of ROR activators and REV-ERB repressors that regulate Bmal1 expression, is thought to "stabilize" core clock function. However, due to functional redundancy and pleiotropic effects of gene deletions, the role of the ROR/REV/Bmal1 loop has not been accurately defined.

Intercellular coupling confers robustness against mutations in the SCN circadian clock network.

Molecular mechanisms of the mammalian circadian clock have been studied primarily by genetic perturbation and behavioral analysis. Here, we used bioluminescence imaging to monitor Per2 gene expression in tissues and cells from clock mutant mice. We discovered that Per1 and Cry1 are required for sustained rhythms in peripheral tissues and cells, and in neurons dissociated from the suprachiasmatic nuclei (SCN).

FKF1 is essential for photoperiodic-specific light signalling in Arabidopsis.

Adaptation to seasonal change is a crucial component of an organism's survival strategy. To monitor seasonal variation, organisms have developed the capacity to measure day length (photoperiodism). Day-length assessment involves the photoperiodic control of flowering in Arabidopsis thaliana, whereby the coincidence of light and high expression of CONSTANS (CO) induces the expression of FLOWERING LOCUS T (FT), leading to flowering in long-day conditions.

Chromatin remodeling protein Chd1 interacts with transcription elongation factors and localizes to transcribed genes.

Transcription in eukaryotes is influenced by the chromatin state of the template, and chromatin remodeling factors have well-documented roles in regulating transcription initiation by RNA polymerase (pol) II. Chromatin also influences transcription elongation; however, little is known about the role of chromatin remodeling factors in this process. Here, we present evidence that the Saccharomyces cerevisiae chromatin remodeling factor Chd1 functions during transcription elongation.