Kikuchi S, Yoshinari K, Ishimaru H, Mizobuchi K
Department of Biophysics and Biochemistry, Faculty of Science, University of Tokyo, Japan.
J Virol. 1988 Dec;62(12):4569-76. doi: 10.1128/JVI.62.12.4569-4576.1988.
Regulation of temporal synthesis of pre-early, early, and late proteins in bacteriophage BF23-infected cells has been studied by using five amber mutants defective in genes 1, 2, 10, 14, and 19. The synthesis of pre-early proteins is negatively regulated by the actions of gene 1, a pre-early gene. The switch from pre-early to early protein synthesis is mainly regulated by the second-step DNA transfer reaction, which is controlled by at least genes 1 and 2. Early proteins can be kinetically and genetically divided into two regulatory classes, designated Ea and Eb. The shutoff of Eb-early protein synthesis is associated with the turn-on of late protein synthesis. This step is controlled by genes 10, 14, and 19. Gene 10 also regulates negatively the synthesis of Ea-early proteins, indicating that this gene has a dual function in the regulation of early protein synthesis. The temporal synthesis of phage-encoded proteins is regulated mainly at the transcriptional level. Evidence is presented indicating that the host RNA polymerase is modified by the interaction with the gene products of genes 2, 10, and 14 (gp2, gp10, and gp14, respectively). gp2 interacts with the enzyme in the earlier stage of infection but is replaced by gp10 in the later stage. This exchange reaction depends on the presence of gp14 and gp19 and is related to the switch from Eb to late protein synthesis. Thus, the regulation of BF23 gene expression occurs in a coordinated manner throughout the development of this phage.
利用在基因1、2、10、14和19中存在缺陷的五个琥珀突变体，研究了噬菌体BF23感染细胞中前早期、早期和晚期蛋白质的时序合成调控。前早期蛋白质的合成受到前早期基因1的作用的负调控。从前早期到早期蛋白质合成的转换主要受第二步DNA转移反应调控，该反应至少由基因1和2控制。早期蛋白质在动力学和遗传学上可分为两个调控类别，分别称为Ea和Eb。Eb早期蛋白质合成的关闭与晚期蛋白质合成的开启相关。这一步骤由基因10、14和19控制。基因10也对Ea早期蛋白质的合成起负调控作用，表明该基因在早期蛋白质合成调控中具有双重功能。噬菌体编码蛋白质的时序合成主要在转录水平受到调控。有证据表明，宿主RNA聚合酶通过与基因2、10和14的基因产物（分别为gp2、gp10和gp14）相互作用而被修饰。gp2在感染早期与该酶相互作用，但在后期被gp10取代。这种交换反应依赖于gp14和gp19的存在，并且与从Eb到晚期蛋白质合成的转换有关。因此，BF23基因表达的调控在该噬菌体的整个发育过程中以协调的方式发生。
