Evans D G, Evans D J, Lampert H C, Graham D Y
Department of Medicine, Baylor College of Medicine, Houston, Texas, USA.
Am J Gastroenterol. 1995 Aug;90(8):1282-8.
To assess the degree of restriction fragment length polymorphism (RFLP) in the Helicobacter pylori adhesin gene hpaA and to determine the molecular basis of RFLP in this gene.
A 375-bp, polymerase chain reaction-amplified internal sequence of hpaA, obtained from 50 different H. pylori isolates, was restricted with Sau3A and HinfI, individually. Polymerase chain reaction products representing different RFLP types were sequenced.
Seven different polymorphic types were found in hpaA. Base substitutions at only four positions, two in Sau3A and two in HinfI sites, account for all of the RFLP types, including the size of the restriction fragments determined by gel electrophoresis. Most, 90%, of the base substitutions are very conservative, i.e., either do not change the encoded amino acid or substitute a homologous amino acid, and cause no detectable antigenic or functional effect on hpaA. The region of hpaA encoding the receptor-binding motif was particularly well conserved.
RFLP typing of hpaA using Sau3A and HinfI provides an additional tool for comparing the genetic relatedness of H. pylori isolates collected during epidemiological and/or treatment studies.
评估幽门螺杆菌黏附素基因hpaA中的限制性片段长度多态性（RFLP）程度，并确定该基因中RFLP的分子基础。
从50株不同的幽门螺杆菌分离株中获得hpaA的一段375 bp聚合酶链反应扩增的内部序列，分别用Sau3A和HinfI进行酶切。对代表不同RFLP类型的聚合酶链反应产物进行测序。
在hpaA中发现了7种不同的多态性类型。仅4个位置的碱基替换，其中2个在Sau3A位点，2个在HinfI位点，就解释了所有的RFLP类型，包括通过凝胶电泳确定的限制性片段大小。大多数（90%）碱基替换非常保守，即要么不改变编码的氨基酸，要么替换同源氨基酸，并且对hpaA没有可检测到的抗原或功能影响。hpaA编码受体结合基序的区域特别保守。
使用Sau3A和HinfI对hpaA进行RFLP分型为比较在流行病学和/或治疗研究中收集的幽门螺杆菌分离株的遗传相关性提供了一种额外的工具。
