Localization and pathogenic role of the cysteine protease dentipain in Treponema denticola

Treponema denticola is a major etiological agent of chronic periodontis. Dentipain is one of the virulence factors of this microorganism. The localization and function of the protein has yet to be clarified although it has shown to be involved in the virulence of T. denticola. Therefore, this study aimed to characterize the role of dentipain in T. denticola. To investigate the function of dentipain, dentipain deficient mutant was constructed using an ermFermAM cassette and gene expression profile of the mutant was evaluated by microarray analysis. Growth rate of the dentipain-deficient mutants was smaller than that of the wild-type strain. In the mutant. Thirty-five genes in differentially expressed genes by the microarray analysis annotated as membrane or plasma membrane in gene ontology. Hydrophobicity of the mutant were higher than that of the wild-type strain. These findings suggest that dentipain involved in the surface characteristics and growth of T. denticola. Comparison of 2 strains of T. denticola. Treponema denticola ATCC 35405 and YM-3 were cultured in TYGVS medium for 24-48 h. Profile of gene expression of T. denticola YM-3 was compared to that of ATCC 35405.

齿密螺旋体（Treponema denticola）是慢性牙周炎的主要致病原。齿密螺旋体蛋白酶（dentipain）是该微生物的毒力因子之一。尽管已有研究证实其参与齿密螺旋体的致病过程，但该蛋白的具体定位与功能仍有待阐明。因此，本研究旨在解析齿密螺旋体蛋白酶在齿密螺旋体中的作用。为探究该蛋白酶的功能，研究人员利用ermFermAM盒构建了齿密螺旋体蛋白酶缺陷突变株，并通过微阵列（microarray）分析对该突变株的基因表达谱进行了评估。齿密螺旋体蛋白酶缺陷突变株的生长速率低于野生型菌株。在该突变株中，经微阵列分析筛选得到的差异表达基因里，有35个在基因本体论（Gene Ontology）中被注释为膜蛋白或质膜蛋白。该突变株的疏水性高于野生型菌株。上述研究结果表明，齿密螺旋体蛋白酶参与调控齿密螺旋体的表面特性与生长过程。本研究还对两株齿密螺旋体菌株进行了比较：将ATCC 35405与YM-3株齿密螺旋体在TYGVS培养基中培养24~48小时，并对比了YM-3株与ATCC 35405株的基因表达谱。