Debrouwere L, Van Montagu M, Schell J
Mol Gen Genet. 1980;179(1):81-8. doi: 10.1007/BF00268449.
The ral gene of phage lambda has previously been shown to counteract host controlled restriction and to enhance DNA modification in Escherichia coli (Zabeau et al., 1980). The studies presented in this paper demonstrate that although ral plays only a minor role in the lytic development of phage lambda, it counteracts different E. coli functions, which, like the E. coli restriction system, are ATP dependent. First, ral was found to specifically decrease the efficiency of recombination mediated by the RecBC pathway. Secondly, we observed that E. coli strains in which ral is constitutively expressed, exhibit phenotypes analogous to those of strains carrying mutations in the transcription termination factor rho. In addition, in rho deficient strains general recombination and host controlled restriction are both reduced. These findings strongly suggest that ral might be a second anti-termination function, which in contrast to the lambda N gene product directly antagonizes rho.
噬菌体λ的ral基因先前已被证明可对抗宿主控制的限制作用，并增强大肠杆菌中的DNA修饰作用（扎博等，1980年）。本文所呈现的研究表明，尽管ral在噬菌体λ的裂解发育中仅起次要作用，但它可对抗不同的大肠杆菌功能，这些功能与大肠杆菌限制系统一样，都依赖于ATP。首先，发现ral可特异性降低由RecBC途径介导的重组效率。其次，我们观察到ral组成型表达的大肠杆菌菌株表现出与转录终止因子rho发生突变的菌株类似的表型。此外，在rho缺陷型菌株中，一般重组和宿主控制的限制作用均降低。这些发现有力地表明，ral可能是第二种抗终止功能，与λ N基因产物不同，它直接拮抗rho。
