Journal
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
Volume 107, Issue 7, Pages 3263-3268Publisher
NATL ACAD SCIENCES
DOI: 10.1073/pnas.0909924107
Keywords
CikA; circadian clock; LabA; SasA; transcriptional feedback
Categories
Funding
- Ministry of Education, Culture, Sports, Science and Technology of Japan [15GS0308]
- Japan Society for the Promotion of Science [17370088]
- Grants-in-Aid for Scientific Research [17370088, 15GS0308] Funding Source: KAKEN
Ask authors/readers for more resources
Circadian kaiBC expression in the cyanobacterium Synechococcus elongatus PCC 7942 is generated by temporal information transmission from the KaiABC-based circadian oscillator to RpaA, a putative transcriptional factor, via the SasA-dependent positive pathway and the LabA-dependent negative pathway which is responsible for feedback regulation of KaiC. However, the labA/sasA double mutant has a circadian kaiBC expression rhythm, suggesting that there is an additional circadian output pathway. Here we describe a third circadian output pathway, which is CikA-dependent. The cikA mutation attenuates KaiC overexpression-induced kaiBC repression and exacerbates the low-amplitude phenotype of the labA mutant, suggesting that cikA acts as a negative regulator of kaiBC expression independent of the LabA-dependent pathway. In the labA/sasA/cikA triple mutant, kaiBC promoter activity becomes almost arrhythmic, despite preservation of the circadian KaiC phosphorylation rhythm, suggesting that CikA largely accounts for the residual kaiBC expression rhythm observed in the labA/sasA double mutant. These results also strongly suggest that transcriptional regulation in the labA/sasA/cikA triple mutant is insulated from the circadian signals of the KaiABC-based oscillator. Based on these observations, we propose a model in which temporal information from the KaiABC-based circadian oscillator is transmitted to gene expression through three separate output pathways.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available