The essentiality and involvement of Streptococcus intermedius histone-like DNA-binding protein in bacterial viability and normal growth
The essentiality and involvement of Streptococcus intermedius histone-like DNA-binding protein in bacterial viability and normal growth
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DOI：
10.1111/j.1365-2958.2008.06232.x
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发表时间：
2008-06-01
影响因子：
3.6
通讯作者：
Miyake, Yoichiro
中科院分区：
文献类型：
--
作者：
Liu, Dali;Yumoto, Hiromichi;Miyake, Yoichiro
中间链球菌组蛋白样dna结合蛋白（Si-HLP）是一种同型二聚体蛋白，与大肠杆菌HU一样是一种核相关蛋白（NAP）。在大肠杆菌中，HU作为结构因子和调节因子都起着重要的作用，但对大肠杆菌的生存并不是必需的。已发现链球菌HLP结合宿主细胞并诱导细胞因子产生，但其生理作用仍不清楚。在本研究中，我们利用基因插入敲除和四环素调节的反义RNA表达技术，确定了Si-HLP是否对中间链酵母菌的生存和正常生长至关重要。si - hlp下调后，中间葡萄球菌的形态和表面性质发生了变化。下调Si-HLP导致扩大的类核填充细胞内空间。通过实时PCR和反转录PCR，发现反义si - help rna表达菌株的多个基因转录水平被激活或抑制，包括毒力相关因子。综上所述，这些数据表明Si-HLP是中间葡萄球菌控制类核结构和基因转录谱的重要NAP。
Streptococcus intermedius histone-like DNA-binding protein (Si-HLP) is a homodimeric protein and, conserved with Escherichia coli HU, a well-documented nucleoid-associated protein (NAP). In E. coli, HU plays important roles as both structural and regulatory factors, but it is not essential for E. coli viability. Streptococcal HLP has been found to bind host cells and induce cytokine production, but its physiological role remains poorly defined. In the present study, using gene insertion knockout and tetracycline-regulated antisense RNA expression techniques, we determined whether Si-HLP is essential for bacterial viability and normal growth in S. intermedius. The Si-HLP-downregulated S. intermedius strain showed alterations in its morphology and surface properties. Downregulation of Si-HLP led to an expanded nucleoid to fill the intracellular space. Transcription levels of several genes, including virulence-associated factors, were found to be activated or repressed in the antisense Si-hlp RNA-expressing strain by real-time PCR and reverse-transcription PCR. Collectively, these data suggest that Si-HLP serves as an essential NAP governing the nucleoid architecture and controlling the gene transcription profile in S. intermedius.