Cloning and gene assignment of mRNAs of human parainfluenza virus 3.

Cytoplasmic poly(A)-containing RNA from parainfluenza virus 3-infected cells was used as template to construct a cDNA library that was cloned into the EcoRV site of the plasmid pMG5. The resulting clones were screened with [32P]-labeled cDNA probes made from infected and mock-infected cell mRNAs. The virus specificity of the clones was confirmed by Northern blot hybridization. The viral clones were grouped into five different families by hybridization with individual size-selected reverse transcripts representing the major classes of poly(A)+-RNA from virus-infected cells. The five groups were shown to be unrelated on the basis of cross-colony hybridization and corresponded to five unique classes of intracellular viral poly(A)+-RNAs. Clones representing the NP and P genes of PIV-3 were identified by both hybrid-selected and hybrid-arrested translation. Clones specific for the P gene selected mRNA that directed the synthesis of P protein and another polypeptide of 21 kDa. This additional polypeptide comigrated with protein VP8 previously identified in virions and in infected cell lysates.