title: Two regions of the P protein are required to be active with the L protein for human parainfluenza virus type 1 RNA polymerase activity.
abstract: The paramyxovirus P protein is an essential component of the viral RNA polymerase composed of P and L proteins. In this study, we characterized the physical and functional interactions between P and L proteins using human parainfluenza virus type 1 (hPIV1) and its counterpart Sendai virus (SV). The hPIV1 P and SV L proteins or the SV P and hPIV1 L proteins formed complexes detected by anti-P antibodies. Functional analysis using the minigenome SV RNA containing CAT gene indicated that the hPIV1 P--SV L complex, but not the SV P--hPIV1 L complex, was biologically active. Mutant SV P or hPIV1 P cDNAs, which do not express C proteins, showed the same phenotype with wild-type P cDNAs, indicating that C proteins are not responsible for the dysfunction of SV P--hPIV1 L polymerase complex. Using the chimeric hPIV1/SV P cDNAs, we identified two regions (residues 387--423 and 511--568) on P protein, which are required for the functional interaction with hPIV1 L. These regions overlap with a previously identified domain for oligomer formation and binding to nucleocapsids. Our results indicate that in addition to a P--L binding domain, hPIV1 L requires a specific region on P protein to be biologically functional as a polymerase.
authors.affiliation: Department of Virology and Molecular Biology, St. Jude Children's Research Hospital, 332 N. Lauderdale St., Memphis, Tennessee 38105-2794, USA.
authors.forename: T
authors.initials: T
authors.lastname: Bousse
authors.forename: T
authors.initials: T
authors.lastname: Takimoto
authors.forename: T
authors.initials: T
authors.lastname: Matrosovich
authors.forename: A
authors.initials: A
authors.lastname: Portner
mesh_terms: D000595:Amino Acid Sequence; D012321:DNA-Directed RNA Polymerases / Q000378:metabolism*; D006367:HeLa Cells; D006801:Humans; D008969:Molecular Sequence Data; D019251:Nucleocapsid / Q000378:metabolism; D010222:Parainfluenza Virus 1, Human / Q000378:metabolism; D010750:Phosphoproteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D018108:Respirovirus / Q000378:metabolism; D014162:Transfection; D014764:Viral Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*
chemical_list: D010750:Phosphoproteins; D014764:Viral Proteins; C051221:nonstructural C protein, Sendai virus; C068855:P protein, parainfluenza virus 1; C064365:L protein, Sendai virus; D012321:DNA-Directed RNA Polymerases