Mechanism of transcription activation at the comG promoter by the competence transcription factor ComK of Bacillus subtilisSusanna, KA., van der Werff, AF., den Hengst, CD., Calles, B., Salas, M., Venema, G., Hamoen, LW. & Kuipers, OP., Feb-2004, In : Journal of Bacteriology. 186, 4, p. 1120-1128 9 p.
Research output: Contribution to journal › Article › Academic › peer-review
The development of genetic competence in Bacillus subtilis is regulated by a complex signal transduction cascade, which results in the synthesis of the competence transcription factor, encoded by comK. ComK is required for the transcription of the late competence genes that encode the DNA binding and uptake machinery and of genes required for homologous recombination. In vivo and in vitro experiments have shown that ComK is responsible for transcription activation at the comG promoter. In this study, we investigated the mechanism of this transcription activation. The intrinsic binding characteristics of RNA polymerase with and without ComK at the comG promoter were determined, demonstrating that ComK stabilizes the binding of RNA polymerase to the comG promoter. This stabilization probably occurs through interactions with the upstream DNA, since a deletion of the upstream DNA resulted in an almost complete abolishment of stabilization of RNA polymerase binding. Furthermore, a strong requirement for the presence of an extra AT box in addition to the common ComK-binding site was shown. In vitro transcription with B. sublilis RNA polymerase reconstituted with wild-type alpha-subunits and with C-terminal deletion mutants of the alpha-subunits was performed, demonstrating that these deletions do not abolish transcription activation by ComK. This indicates that ComK is not a type I activator. We also show that ComK is not required for open complex formation. A possible mechanism for transcription activation is proposed, implying that the major stimulatory effect of ComK is on binding of RNA polymerase.
|Number of pages||9|
|Journal||Journal of Bacteriology|
|Publication status||Published - Feb-2004|
- POLYMERASE ALPHA-SUBUNIT, PROTEIN-PROTEIN CONTACTS, CAP-DEPENDENT PROMOTERS, INTEGRATION HOST FACTOR, COLI RNA-POLYMERASE, ESCHERICHIA-COLI, PROKARYOTIC TRANSCRIPTION, BACTERIAL PROMOTERS, REGULATORY PROTEIN, GENETIC COMPETENCE