OpaR Controls a Network of Downstream Transcription Factors in Vibrio parahaemolyticus BB22OP

TR Number
Date
2015-04-22
Journal Title
Journal ISSN
Volume Title
Publisher
Public Library of Science
Abstract

Vibrio parahaemolyticus is an emerging world-wide human pathogen that is associated with food-borne gastroenteritis when raw or undercooked seafood is consumed. Expression of virulence factors in this organism is modulated by the phenomenon known as quorum sensing, which permits differential gene regulation at low versus high cell density. The master regulator of quorum sensing in V. parahaemolyticus is OpaR. OpaR not only controls virulence factor gene expression, but also the colony and cellular morphology associated with growth on a surface and biofilm formation. Whole transcriptome Next Generation sequencing (RNA-Seq) was utilized to determine the OpaR regulon by comparing strains BB22OP (opaR+, LM5312) and BB22TR (∆opaR1, LM5674). This work, using the published V. parahaemolyticus BB22OP genome sequence, confirms and expands upon a previous microarray analysis for these two strains that used an Affymetrix GeneChip designed from the closely related V. parahaemolyticus RIMD2210633 genome sequence. Overall there was excellent correlation between the microarray and RNA-Seq data. Eleven transcription factors under OpaR control were identified by both methods and further confirmed by quantitative reverse transcription PCR (qRT-PCR) analysis. Nine of these transcription factors were demonstrated to be direct OpaR targets via in vitro electrophoretic mobility shift assays with purified hexahistidine-tagged OpaR. Identification of the direct and indirect targets of OpaR, including small RNAs, will enable the construction of a network map of regulatory interactions important for the switch between the nonpathogenic and pathogenic states.

Description
The read data for the V. parahaemolyticus BB22OP LM5312 (opaR+) QS-proficient strain, and V. parahaemolyticus BB22TR LM5674 (∆opaR1) QS-deficient strain, have been deposited in the NCBI Sequence Read Archive (SRA) with accession numbers GSM1297676 and GSM1297677, respectively. An Excel file summarizing the differential gene expression in total counts and normalized RPM, using the BB22OP and RIMD2210633 annotations, has been deposited in the NCBI Gene Expression Omnibus (GEO) database (GEO Accession GSE53639).
Keywords
Transcription factors, Gene regulation, Gene expression, Regulator genes, Microarrays, RNA extraction, Chromosome 1, Regulons
Citation
Kernell Burke A, Guthrie LTC, Modise T, Cormier G, Jensen RV, McCarter LL, et al. (2015) OpaR Controls a Network of Downstream Transcription Factors in Vibrio parahaemolyticus BB22OP. PLoS ONE 10(4): e0121863. doi:10.1371/ journal.pone.0121863