Dubow M S, Ryan T
J Gen Microbiol. 1977 Oct;102(2):263-8. doi: 10.1099/00221287-102-2-263.
Host Factor (HF) is a heat-stable RNA-binding protein required along with Qbeta replicase for in vitro transcription of coliphage Qbeta RNA. We have found that HF activity and antigenicity are conserved among certain Gram-negative bacterial species. We examined selected species within the genus Pseudomonas for the presence of the HF polypeptide's antigenicity and Qbeta RNA replication function. While we were unable to detect either of these in Pseudomonas diminuta or Pseudomonas vesicularis, the other eleven species tested contained cross-reacting material to Escherichia coli HF. Furthermore, in six of these eleven species we were able to detect HF activity. The detection of HF structure and function allowed the examined species to be grouped into three categories which we have called 'sets'. The results correlate well with those of previous studies on ribosomal RNA homology (Palleroni et al., 1973).
宿主因子（HF）是一种热稳定的RNA结合蛋白，它与Qβ复制酶一起是噬菌体Qβ RNA体外转录所必需的。我们发现HF活性和抗原性在某些革兰氏阴性细菌物种中是保守的。我们检查了假单胞菌属中的选定物种，以确定是否存在HF多肽的抗原性和Qβ RNA复制功能。虽然我们在矮小假单胞菌或泡囊假单胞菌中均未检测到这些，但测试的其他11个物种含有与大肠杆菌HF发生交叉反应的物质。此外，在这11个物种中的6个物种中，我们能够检测到HF活性。HF结构和功能的检测使所检查的物种分为三类，我们称之为“组”。这些结果与先前关于核糖体RNA同源性的研究结果（Palleroni等人，1973年）非常相关。
