Spliced and unspliced RNAs encoded by virion RNA segment 7 of influenza virus.

Cells infected with the avian influenza virus fowl plague virus, contains three species of polyadenylated RNA which are complementary to virion RNA segment 7. The largest is virtually a complete transcript of vRNA 7, and is the messenger RNA for the matrix protein, but the coding function of the two smaller species, which are approximately 320 and 285 nucleotides long (excluding poly(A)), is unknown. It is likely however that at least one of the small RNAs encodes a new virus polypeptide which has been predicted from the nucleotides sequence of vRNA 7. The major part of each RNA maps within about 300 nucleotides from the 5'-terminus of vRNA 7, but the larger species also contains additional sequences derived from the 3' terminus. Production of the two small RNAs may involve alternative patterns of splicing of the matrix protein mRNA.