The leader sequence from the 5'-terminus to the A-protein initiation codon in MS2-virus RNA

RNA fragments of different chain length, each containing the 5'-terminal guanosine tetraphosphate (pppGp) of bacteriophage-MS2 RNA, have been isolated from partial ribonuclease digests of the viral RNA. The longest fragment overlaps with the ribosomalbinding site of the A-protein cistron. The base sequence has been established for the major part. The results directly confirm that the A-protein cistron is closest to the 5'-terminus. Its initiating (AUG) codon starts at position 130, being preceded by an untranslated sequence of 129 nucleotides.