The 1A protein gene of human respiratory syncytial virus: nucleotide sequence of the mRNA and a related polycistronic transcript.

The 1A mRNA is the smallest mRNA of human respiratory syncytial (RS) virus and encodes a single protein of approximate molecular weight 9500 as estimated previously by gel electrophoresis. The nucleotide sequence of the 1A mRNA, determined from several full-length cDNA clones, is reported. The 1A mRNA consists of 405 nucleotides, exclusive of poly(A), with relatively long nontranslated regions at the 5' and 3' ends (84 and 126 nucleotides, respectively). The sequences at the 5' and 3' termini of the 1A mRNA conform to the previously described conserved consensus sequences for RS virus mRNAs. The major open reading frame of the 1A mRNA codes for a hydrophobic polypeptide of 64 amino acids with a calculated molecular weight of 7536. The 5' terminus of the 1A mRNA was mapped and sequenced by primer extension under conditions for sequencing by partial chain termination. These experiments also identified a population of polycistronic RNA having the general structure: 5' M protein mRNA-1A mRNA 3'. This polytranscript was sequenced in order to determine the intergenic sequence. In the polytranscript, the nucleotide sequence of the M gene is followed by, in mRNA sense, six A residues and the intergenic sequence 5' ... UAUACACNN (N represents unidentified nucleotide).