Circadian transcriptional regulation by the posttranslational oscillator without de novo clock gene expression in Synechococcus.

ABSTRACT: Circadian rhythms are a fundamental property of most organisms, from cyanobacteria to humans. In the unicellular obligately photoautotrophic cyanobacterium Synechococcus elongatus PCC 7942, essentially all promoter activities are controlled by the KaiABC-based clock under continuous light conditions. When Synechococcus cells are transferred from the light to continuous dark (DD) conditions, the expression of most genes, including the clock genes kaiA and kaiBC, is rapidly down-regulated, whereas the KaiC phosphorylation cycle persists. Therefore, we speculated that the posttranslational oscillator might not drive the transcriptional circadian output without de novo expression of the kai genes. Here we show that the cyanobacterial clock regulates the transcriptional output even in the dark.

SUBMITTER: Hosokawa N 

PROVIDER: S-EPMC3174641 | biostudies-literature | 2011 Sep

REPOSITORIES: biostudies-literature