Physiological function of histone-like HupB in Aeromonas hydrophila

Abstract:

[Objective] The DNA-binding protein HU is a histone-like protein involved in the recombination and repair of bacterial DNA and plays a regulatory role in the transcription of bacteria, whereas the role of this protein in the physiological activities of bacteria remains unknown. In order to learn more about the HU protein, we investigated the physiological function of HupB. [Methods] We constructed a hupB-deleted strain of Aeromonas hydrophila by using homologous recombination technology and then determined the physiological phenotype of the strain. [Results] The deletion of hupB gene significantly enhanced the hemolysis, extracellular protease activity, and motility, while it significantly reduced the biofilm formation. The biofilm formation was restored in ΔhupB::hupB. Further, label-free quantitative proteomics analysis was performed to study the differentially expressed proteins between the wild type and ΔhupB, which revealed 235 up-regulated proteins and 224 down-regulated proteins in ΔhupB. The bioinformatics analysis showed that the differentially expressed proteins were involved in a variety of biological processes such as protein translation, biofilm formation, and signal transduction. [Conclusion] The HupB protein can remarkably affect the biofilm formation of A. hydrophila. The results provide a theoretical basis for better understanding the regulatory role of HupB in the physiological activities of A. hydrophila.