The syp enhancer sequence plays a key role in transcriptional activation by the sigma54-dependent response regulator SypG and in biofilm formation and host colonization by Vibrio fischeri Journal Article


Authors: Ray, V. A.; Eddy, J. L.; Hussa, E. A.; Misale, M.; Visick, K. L.
Article Title: The syp enhancer sequence plays a key role in transcriptional activation by the sigma54-dependent response regulator SypG and in biofilm formation and host colonization by Vibrio fischeri
Abstract: Biofilm formation by Vibrio fischeri is a complex process requiring multiple regulators. One such regulator, the NtrC-like response regulator SypG, controls biofilm formation and host colonization by V. fischeri via its impact on transcription of the symbiosis polysaccharide (syp) locus. SypG is predicted to activate syp transcription by binding to the syp enhancer (SE), a conserved sequence located upstream of four syp promoters. In this study, we performed an in-depth analysis of the sequences necessary for SypG to promote syp transcription and biofilm formation. We demonstrated that the SE sequence is necessary for SypG-mediated syp transcription, identified individual bases necessary for efficient activation, and determined that SypG is able to bind to syp promoter regions. We also identified SE sequences outside of the syp locus and established that SypG recognizes these sequences as well. Finally, deletion of the SE sequence upstream of sypA led to defects in both biofilm formation and host colonization that could be restored by re-introducing the SE sequence into its native location in the chromosome. This work thus fills in critical gaps in the Syp regulatory circuit by demonstrating a role for the SE sequence in SypG-dependent control of biofilm formation and host colonization and by identifying new putative regulon members. It may also provide useful insights into other bacteria, such as V. vulnificus and V. parahaemolyticus, that have syp-like loci and conserved SE sequences.
Journal Title: Journal of Bacteriology
ISSN: 1098-5530; 0021-9193
Publisher: Unknown  
Date Published: 2013
Language: ENG
DOI/URL:
Notes: JID: 2985120R; aheadofprint