Birkeland N K, Christie G E, Lindqvist B H
Institute of Medical Biology, University of Tromsö, Norway.
Gene. 1988 Dec 20;73(2):327-35. doi: 10.1016/0378-1119(88)90497-0.
The ogr gene of bacteriophage P2 codes for a basic protein of 72 amino acids which is thought to be essential for activation of P2 late gene transcription. However, conditionally lethal mutations in the ogr gene have never been isolated. We have constructed a P2 ogr deletion mutant by in vitro techniques. This deletion phage, P2-del15, grows in a host which provides the ogr gene product in trans from a plasmid but fails to grow in hosts lacking the ogr plasmid. This demonstrates that the ogr gene is essential for P2 lytic growth. The deletion in P2del15 has removed about half of the carboxy-terminal part of the ogr gene. The transcript from this deletion mutant can be distinguished from the wild-type transcript by S1 nuclease protection. The analysis of such transcripts suggests that the ogr gene product may negatively regulate its own transcription.
噬菌体P2的ogr基因编码一种由72个氨基酸组成的碱性蛋白，该蛋白被认为是激活P2晚期基因转录所必需的。然而，从未分离到ogr基因的条件致死突变体。我们通过体外技术构建了一个P2 ogr缺失突变体。这种缺失噬菌体P2-del15能在从质粒反式提供ogr基因产物的宿主中生长，但在缺乏ogr质粒的宿主中不能生长。这表明ogr基因对P2的裂解生长至关重要。P2del15中的缺失去除了ogr基因羧基末端部分的大约一半。通过S1核酸酶保护可将该缺失突变体的转录本与野生型转录本区分开来。对这些转录本的分析表明，ogr基因产物可能对其自身转录起负调控作用。
