嗜水气单胞菌中类组蛋白HupB生理功能的研究

Physiological function of histone-like HupB in Aeromonas hydrophila

摘要:

【目的】DNA结合蛋白HU蛋白是一类组蛋白样蛋白，其参与细菌DNA的重组与修复，在细菌的转录调控中发挥重要作用，但目前该蛋白对细菌生理功能的影响尚不完全清楚。为了更好地理解HU蛋白，本研究探讨HupB的生理功能。【方法】以嗜水气单胞菌(Aeromonas hydrophila) ATCC 7966为研究材料，利用同源重组技术构建编码HU蛋白β亚基的hupB基因缺失菌株，并对其常见生理表型进行测定。【结果】hupB基因缺失菌株的溶血性、胞外蛋白酶活性和运动性均显著增强，而生物被膜形成能力显著下降，并且ΔhupB::hupB菌株中生物被膜形成能力恢复。进一步利用基于label-free的定量蛋白质组学技术比较了野生株和ΔhupB突变株的差异表达蛋白，发现235个蛋白表达上升，224个蛋白表达下降。生物信息学分析显示hupB敲除后导致蛋白质翻译、生物被膜生成以及信号转导等多个生物过程相关蛋白表达发生变化。【结论】研究结果表明嗜水气单胞菌HupB蛋白能显著影响细菌生物被膜形成能力，以上研究为更好地探究嗜水气单胞菌HupB蛋白对细菌生理功能的调控机制提供理论基础。

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.