Molecular cloning and expression of human parainfluenza virus type 1 L gene

The large (L) protein, a subunit of paramyxovirus RNA polymerase complex is responsible for the majority of enzymic activities involved in viral repli cation and transcription. To gain insight of the functions of the L protein , we cloned the L gene of human parainfluenza virus type 1 (hPIV1) and sequ enced the entire gene. The L gene, which was 6800 nucleotides, encoded a pr otein of 2223 residues with a calculated molecular weight of 253 657. The p redicted amino acid sequence was highly homologous with that of Sendai viru s (SV) L (86% identity). The hPIV1 L protein expressed from the cloned L ge ne bound hPIV1 P expressed in the same cells. When cells were transfected w ith hPIV1 L, P and NP genes together with SV minigenome RNA containing a ch loramphenicol acetyltransferase (CAT) gene (Send-CAT), RNA was transcribed, and CAT proteins were detected. These results indicate that the protein en coded by the cloned hPIV1 L gene was biologically functional and that the h PIV1 polymerase complex recognized SV transcription initiation and terminat ion sequences to produce viral transcripts. (C) 2000 Elsevier Science B.V. All rights reserved.