Involvement of minor components associated with the FimA fimbriae of Porphyromonas gingivalis in adhesive functions
Involvement of minor components associated with the FimA fimbriae of Porphyromonas gingivalis in adhesive functions
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DOI：
10.1099/mic.0.2006/005561-0
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发表时间：
2007-06-01
期刊：
影响因子：
2.8
通讯作者：
Yoshimura, Fuminobu
中科院分区：
文献类型：
--
作者：
Nishiyama, So-ichiro;Murakami, Yukitaka;Yoshimura, Fuminobu
牙龈卟啉单胞菌（Porphyromonas龈卟啉单胞菌）是引起牙周炎的病原体，其FimA菌毛参与了多种致病性，如定植、粘附和聚集。本研究对菌株ATCC 33277中纤溶蛋白基因（fimA）下游的4个开放阅读框（ORF1、ORF2、ORF3和ORF4）进行了检测。ORF2、ORF3和ORF4编码被毛的次要成分，因此分别被重命名为fimC、fimD和fme。免疫印迹分析显示，通过ermF-ermAM插入的fimC或fimD失活，而不是ORF1失活，伴随着下游基因产物的丢失，这提高了fimC， fimD和fme1构成转录单元的可能性。FimA突变体产生FimC和FimD，但从其纯化的菌毛中不含任何蛋白质，这表明FimC和FimD组装到纤原蛋白（FimA）纤维上需要fme。fnc、fmd和fme突变体丧失了自动聚合能力。从这三个突变体中纯化的菌毛对口腔链球菌的甘油醛-3-磷酸脱氢酶和两种细胞外基质蛋白，纤维连接蛋白和I型胶原蛋白的结合活性减弱。这些结果表明，在牙龈假单胞菌成熟FimA菌毛的粘附活性中，fme以及FimC和FimD起着关键作用。
The FimA fimbriae of Porphyromonas gingivalis, the causative agent of periodontitis, have been implicated in various aspects of pathogenicity, such as colonization, adhesion and aggregation. In this study, the four open reading frames (ORF1, ORF2, ORF3 and ORF4) downstream of the fimbrilin gene (fimA) in strain ATCC 33277 were examined. ORF2, ORF3 and ORF4 were demonstrated to encode minor components of the fimbriae and were therefore renamed fimC, fimD and fimE, respectively. Immunoblotting analyses revealed that inactivation of either fimC or fimD by an ermF-ermAM insertion, but not inactivation of ORF1, was accompanied by concomitant loss of the products from the downstream genes, raising the possibility that fimC, fimD and fimE constitute a transcription unit. The fimE mutant produced FimC and FimD, but fimbriae purified from it contained neither protein, suggesting that FimE is required for the assembly of FimC and FimD onto the fimbrilin (FimA) fibre. The fimC, fimD and fimE mutants lost autoaggregation abilities. Fimbriae purified from these three mutants showed attenuated binding activities to glyceraldehyde-3-phosphate dehydrogenase of Streptococcus oralis and to two extracellular matrix proteins, fibronectin and type I collagen. These results suggest that FimE, as well as FimC and FimD, play critical roles in the adhesive activities of the mature FimA fimbriae in P. gingivalis.