幽门螺杆菌iceA1基因地域分布特征

Characteristics of geographical distribution of the Helicobacter pylori iceA1 gene

iceA基因是近年来发现的一种幽门螺杆菌(Helicobacter pylori,H.pylori)毒力相关基因.H.pylori与胃黏膜上皮接触后可引起iceA1基因表达上调,该基因与nlaIIIR基因(位于乳糖奈瑟氏菌)具有相似性,其编码的蛋白质产物具有NlaIIIR样限制性核酸内切酶活性.研究表明,iceA1阳性菌株能引起上皮细胞炎症因子表达水平增高,与胃黏膜炎症程度的发生关系密切.在某些H.pylori菌株中iceA1基因可因存在框移突变而失活或者被iceA2基因取代.在亚洲和非洲的菌株主要表达iceA1基因,美洲大陆则以iceA2多见,而欧洲的iceA基因与亚洲和美洲菌株均具有相似性.H.pylori iceA1基因的地域分布特征很可能反映出不同地区的疾病转归差异性.

The iceA gene has been recently identified as a virulence-related gene of Helicobacter pylori （H. pylori）. The expression of iceA1 is up-regulated in H. pylori contacted with epithelial cells. The iceA1 gene shows a significant homology to the nlaIIIR gene of Neisseria lactamica, which encodes a NlaIII-like restriction endonuclease. iceA1-positive H. pylori strains enhance the expression of inflammatory factors in epithelial cells and are closely associated with the severity of gastric mucosal inflammation. In some strains, the iceA1 gene may be inactivated due to frame shift, or replaced by iceA2. The strains from Asia and Africa mainly express the iceA1, while iceA2 is predominant in American strains. H. pylori strains from Europe show genetic affinity towards both Asia and Europe strains. This pattern of geographical distribution of the H. pylori iceA1 gene possibly reflects different disease profiles of different geographical regions.