Kania S A, Rajeev S, Burns E H, Odom T F, Holloway S M, Bemis D A
University of Tennessee, College of Veterinary Medicine, Department of Comparative Medicine, Knoxville, TN 37996, USA.
Gene. 2000 Oct 3;256(1-2):149-55. doi: 10.1016/s0378-1119(00)00360-7.
Fimbrial proteins play an important role in the binding of Bordetella bronchiseptica to mammalian cells, an event that is key to the pathogenesis of this organism. The fimbrial phenotype of B. bronchiseptica isolates is usually defined serologically by Fim2 and Fim3 antigens. In this study, a previously unidentified fimbrial gene, fimN, was cloned and sequenced. The identity of fimN is based on several observations. The predicted FimN protein has 59.4 and 52. 2% homology with B. bronchiseptica Fim2 and Fim3, respectively, and is similar in size to these fimbriae. fimN, expressed as a recombinant protein, is recognized by mAb prepared against Fim2 from Bordetella pertussis. The fimN promoter region contains a stretch of cytosine residues similar in length to those of other fimbrial genes expressed by Bordetella species. It also has an activator binding region, upstream from the C-stretch, that closely resembles a corresponding bvg regulated region in fim2, fim3, and fimX. The fimN gene was isolated from a cosmid prepared with B. bronchiseptica genomic DNA that restored normal properties of cellular adhesion to an adhesion deficient strain of B. bronchiseptica. As such, FimN may be a previously overlooked fimbrial antigen and may play an important role in the pathogenicity of B. bronchiseptica.
菌毛蛋白在支气管败血波氏杆菌与哺乳动物细胞的结合过程中发挥重要作用，这一过程是该菌发病机制的关键环节。支气管败血波氏杆菌分离株的菌毛表型通常通过Fim2和Fim3抗原进行血清学定义。在本研究中，一个先前未被鉴定的菌毛基因fimN被克隆并测序。fimN的鉴定基于以下几点观察。预测的FimN蛋白与支气管败血波氏杆菌的Fim2和Fim3分别具有59.4%和52.2%的同源性，且大小与这些菌毛相似。以重组蛋白形式表达的fimN可被针对百日咳博德特氏菌Fim2制备的单克隆抗体识别。fimN启动子区域含有一段胞嘧啶残基序列，其长度与博德特氏菌属表达的其他菌毛基因相似。它在C序列上游还有一个激活剂结合区域，与fim2、fim3和fimX中相应的bvg调控区域极为相似。fimN基因是从用支气管败血波氏杆菌基因组DNA制备的黏粒中分离出来的，该黏粒恢复了支气管败血波氏杆菌黏附缺陷菌株的细胞黏附正常特性。因此，FimN可能是一种先前被忽视的菌毛抗原，可能在支气管败血波氏杆菌的致病性中发挥重要作用。
