An amino-proximal domain of the L protein binds to the P protein in the measles virus RNA polymerase complex.
The RNA polymerase of measles virus consists of two virus-encoded subunits, the L and P proteins with 2183 and 507 amino acids, respectively. When these proteins were coexpressed from plasmids in a mammalian expression system, a complex was formed as detected by the coimmunoprecipitation of the L protein with the P protein by anti-P antibodies. Pulse-chase experiments showed that complex formation increased the stability of the L protein. We have used the coimmunoprecipitation assay in conjunction with a series of C-terminal truncations of the L protein to map the region of the L protein which is involved in complex formation with the P protein. Mutant L proteins consisting of the N-terminal 1139, 916, 511, and 408 amino acids all bound to the P protein. An L protein truncation consisting of only the N-terminal 292 amino acids, which deleted part of the conserved domain I, however, did not bind the P protein. The data show that the N-terminal 408 amino acids of the L protein contain the P binding domain and suggest that domain I within this region of the L proteins of (-) strand RNA viruses may be important for RNA polymerase complex formation.
Department of Immunology and Medical Microbiology, University of Florida College of Medicine, Gainesville 32610.
S M
SM
Horikami
S
S
Smallwood
B
B
Bankamp
S A
SA
Moyer
D000595:Amino Acid Sequence; D000818:Animals; D001704:Biopolymers / Q000378:metabolism; D002460:Cell Line; D012321:DNA-Directed RNA Polymerases / Q000096:biosynthesis / Q000378:metabolism*; D005822:Genetic Vectors; D008459:Measles virus / Q000201:enzymology*; D008969:Molecular Sequence Data; D011233:Precipitin Tests; D011485:Protein Binding; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis; D017384:Sequence Deletion; D014616:Vaccinia virus; D014764:Viral Proteins / Q000096:biosynthesis / Q000378:metabolism*
D001704:Biopolymers; D011993:Recombinant Fusion Proteins; D014764:Viral Proteins; D012321:DNA-Directed RNA Polymerases