[Influence of protein bound with single-stranded DNA on the synthesis of RNA and poly(A). III. Protein product of F1 gene 5].

Influence of the protein product of F1 phage gene 5 (protein 5) on the synthesis RNA and poly(A) in vitro was studied. It has been shown, that protein 5 has no effect on the transcription of the native DNA by E. coli RNA-polymerase, but completely prevents RNA and poly(A) synthesis on the denatured or single-stranded DNA at the protein/DNA ratio 10:1. Protein 5 inhibits poly(A) synthesis with oligo(dT)9 and oligo(dT)12 as a template, preventing binding of enzyme to the oligonucleotide. After the initiation of the poly(A) synthesis the inhibition becomes considerably wearer. The biological function of the inhibition of the transcription by "unwinding" proteins is discussed.