Abstract： Objective： To establish the chromatin immunocoprecipitation-real-time quantitative PCR (ChIP-qPCR) assay for Vibrio parahemolyticus QsvR. Methods: The QsvR fragments labeled with 2×Flag tag were transferred into ΔqsvR by heat shock transformation and transformation binding. Arabinose induced the expression of QsvR-2×Flag protein, which was crosslinked with genomic DNA through formaldehyde to form 2×Flag-QsvR-DNA complex. The genomic DNA was ultrasonically cleaved into fragments ranging in size from 100—1 000 bp, and the protein-DNA complex was precipitated by specific antigen-antibody reaction. The cross-linked DNA was de-crosslinked by high salt and heating, and the DNA was recovered for qPCR quantitative DNA to analyze the binding of QsvR and target genes in V. parahemolyticus. Results: The experimental strain ΔqsvR/pBAD33-qsvR-2×Flag was successfully constructed. The IP expression of aphA, opaR, exsB and vtrA of the strain induced by arabinose was significantly higher than that of the control strain. The results indicated that QsvR could bind aphA, opaR, exsB and vtrA in V. parahaemolyticus. Conclusion: The ChIP-qPCR assay of V. parahemolyticus QsvR was established successfully, which can be used to study proteinDNA interaction in prokaryotes. ［Key words］ChIP-qPCR; protein-DNA complex; Vibrio parahaemolyticus; QsvR
