O'Reilly C, Turner P D, Smith-Keary P F, McConnell D J
Mol Gen Genet. 1984;196(1):152-7. doi: 10.1007/BF00334108.
Genes have been cloned from Salmonella typhimurium which when present on the multicopy plasmid pBR322 in the E. coli strain NT31 confer a Gua+ phenotype on this strain. NT31 is a purE gpt double mutant and it was expected that a Gua+ phenotype could be conferred on it by the cloning of either gpt or purE. It was, however found that in addition to these two loci the molecular cloning of another gene, which has been identified as hpt, in pBR322 confers a Gua+ phenotype on NT31. This result is explained by the overproduction of the hpt gene product, hypoxanthine phosphoribosyl transferase, which compensates for the lack of the gpt product guanine-xanthine phosphoribosyl transferase. Restriction analysis of the three loci, gpt, hpt and purE is also presented.
已从鼠伤寒沙门氏菌中克隆出一些基因，当这些基因存在于大肠杆菌NT31菌株的多拷贝质粒pBR322上时，会赋予该菌株鸟嘌呤（Gua+）表型。NT31是嘌呤核苷酸生物合成途径中purE和gpt的双突变体，预期通过克隆gpt或purE可赋予其Gua+表型。然而，发现除了这两个基因座外，另一个已鉴定为hpt的基因在pBR322中的分子克隆也能赋予NT31 Gua+表型。这一结果的解释是hpt基因产物次黄嘌呤磷酸核糖转移酶的过量产生，它弥补了gpt产物鸟嘌呤-黄嘌呤磷酸核糖转移酶的缺失。文中还给出了gpt、hpt和purE这三个基因座的限制性分析。
