ComWΔ6 Stimulates Transcription of Pneumococcal Competence Genes in vitro

• Main Authors: Nicole L. Inniss, Donald A. Morrison
• Format: Article
• Language: English
• Published: Frontiers Media S.A. 2020-05-01
• Series: Frontiers in Molecular Biosciences
• Subjects: alternative sigma factor; S. pneumoniae competence; genetic transformation; ComW; transcription
• Online Access: https://www.frontiersin.org/article/10.3389/fmolb.2020.00061/full

The alternative streptococcal σ-factor and master competence regulator, σX, stimulates transcription from competence promoters, in vitro. As the only known alternative σ-factor in streptococci, σX expression is tightly controlled in each species and has a specific physiological role. Pneumococcal transformation also requires the DNA binding activity of ComW, a known σX activator and stabilizer. Mutations to the housekeeping σ factor, σA, partially alleviate the ComW requirement, suggesting that ComW is a key player in the σ factor swap during the pneumococcal competence response. However, there is no evidence of a direct ComW – RNA polymerase interaction. Furthermore, if and how ComW functions directly at combox promoters is still unknown. Here we report that a DNA-binding ComW variant, ComΔ6, can stimulate transcription from σX promoters in vitro.