The ral gene phage λ

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Abstract
The ral gene of phage λ has previously been shown to counteract host controlled restriction and the 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 λ, 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 λN gene product directly antagonizes rho.