Download MendeleyMechanism and reconstitution of circadian transcription in cyanobacteria.
Fang, M., Gu, Y., Leanca, M., Matyszewski, M., LiWang, A., Yuzenkova, Y., Corbett, K.D., Golden, S.S.(2026) Nat Struct Mol Biol 33: 275-281
- PubMed: 41667880
- DOI: https://doi.org/10.1038/s41594-025-01740-0
- Primary Citation of Related Structures:
9DVS, 9DVT, 9DVU - PubMed Abstract:
Circadian biological clocks evolved across kingdoms of life as an adaptation to predictable cycles of sunrise and sunset. In the cyanobacterium Synechococcus elongatus, a protein-based clock precisely controls when different genes are turned on and off during the 24-h day but the phasing mechanism remains unclear. Here we show the molecular basis of this regulation and reconstitute clock-controlled transcription in vitro using purified components. Biochemical and structural analyses revealed that the clock-regulated transcription factor RpaA can function as either an activator or a repressor of cyanobacterial RNA polymerase, depending on its binding position relative to core promoter elements. Leveraging the repressor mechanism, we developed a heterologous in vitro system driven by bacteriophage T7 RNA polymerase that sustains circadian transcription for multiple days. These findings explain how a single clock output generates opposite phases of gene expression and define the minimal components for circadian clock function, enabling synthetic or biotechnological applications.
- Center for Circadian Biology, University of California, San Diego, La Jolla, CA, USA.
Organizational Affiliation:
