title: Genomic analysis identifies a transcription-factor binding motif regulating expression of the alpha C protein in Group B Streptococcus.
abstract: The virulence-associated alpha C protein (ACP) of Group B Streptococcus (GBS) facilitates the bacterial interaction with host epithelial cells. We previously demonstrated that phase-variable expression of ACP is controlled by variation in short-sequence repeat sequences present upstream of the promoter of bca, the gene encoding ACP. To determine if trans-acting transcriptional control also influences ACP expression, we developed an in silico prediction algorithm that identified a potential transcription-factor binding motif (TTT-N(6)-ATAT) in the bca upstream region. In vitro reporter gene expression studies confirmed that this motif is required for full ACP expression, and DNA-binding assays with a GBS protein extract demonstrated that the predicted site is bound by a protein. This approach demonstrates the utility of in silico genomic predictive methods in the study of GBS regulatory mechanisms.
authors.affiliation: Channing Laboratory, Brigham and Women's Hospital, Boston, MA 02115, USA.
authors.forename: David C
authors.initials: DC
authors.lastname: Klinzing
authors.forename: Lawrence C
authors.initials: LC
authors.lastname: Madoff
authors.forename: Karen M
authors.initials: KM
authors.lastname: Puopolo