The genome organization of potato virus M RNA.

The 8534 nucleotide sequence of the genome of the carlavirus, potato virus M (PVM), has been determined. The sequence contains six large open reading frames (ORFs) and non-coding regions consisting of 75 nucleotides at the 5' end, 70 nucleotides followed by a poly(A) tail at the 3' end and 38 and 21 nucleotides between three large blocks of coding sequences. The ORF beginning at the first initiation codon at nucleotide 76 encodes a polypeptide of 223K which, according to its primary sequence analysis, seems to be a virus RNA replicase. The next coding block consists of three ORFs encoding polypeptides of 25K, 12K and 7K. The third block consists of two ORFs encoding polypeptides of 34K (PVM coat protein) and 11K. The 11K polypeptide contains a pattern resembling the consensus for a metal-binding nucleic acid-binding 'finger'.