Download MendeleyDNA looping mediates cooperative transcription activation.
Han, S.J., Jiang, Y.L., You, L.L., Shen, L.Q., Wu, X., Yang, F., Cui, N., Kong, W.W., Sun, H., Zhou, K., Meng, H.C., Chen, Z.P., Chen, Y., Zhang, Y., Zhou, C.Z.(2024) Nat Struct Mol Biol 31: 293-299
- PubMed: 38177666
- DOI: https://doi.org/10.1038/s41594-023-01149-7
- Primary Citation of Related Structures:
8H3V, 8H3Z, 8H40 - PubMed Abstract:
Transcription factors respond to multilevel stimuli and co-occupy promoter regions of target genes to activate RNA polymerase (RNAP) in a cooperative manner. To decipher the molecular mechanism, here we report two cryo-electron microscopy structures of Anabaena transcription activation complexes (TACs): NtcA-TAC composed of RNAP holoenzyme, promoter and a global activator NtcA, and NtcA-NtcB-TAC comprising an extra context-specific regulator, NtcB. Structural analysis showed that NtcA binding makes the promoter DNA bend by ∼50°, which facilitates RNAP to contact NtcB at the distal upstream NtcB box. The sequential binding of NtcA and NtcB induces looping back of promoter DNA towards RNAP, enabling the assembly of a fully activated TAC bound with two activators. Together with biochemical assays, we propose a 'DNA looping' mechanism of cooperative transcription activation in bacteria.
Organizational Affiliation:
School of Life Sciences and Biomedical Sciences and Health Laboratory of Anhui Province, Division of Life Sciences and Medicine, University of Science & Technology of China, Hefei, China.
