title: Studies on the rabies virus RNA polymerase: 3. Two-dimensional electrophoretic analysis of the multiplicity of non-catalytic subunit (P protein).
abstract: We described previously (Takamatsu et al., 1998. Microbiol. Immunol. 42: 761-771) the rabies virus P protein as being composed of several components of different sizes, among which the full-sized major components were termed as p40 and p37 according to their electrophoretic mobilities, and radiolabeling studies with [32P]phosphate implied that p40 was a hyperphosphorylated form. We further examined here these proteins by two-dimensional (2-D) gel electrophoresis and immunoblotting, showing that a major component, p37, was composed of multiply modified subcomponents of different pIs (termed p37-1, p37-2, p37-3, etc., based on their acidity) in the virion and infected cells, but the unmodified precursor (termed p37-0) was little in amount. The viral nucleocapsid (NC)-bound P proteins were composed of multiple forms of p37 (the major one was p37-1) and also a minor component, p40-1. P proteins which were bound to newly synthesized free N proteins were mostly composed of p37-1, indicating that hyperphosphorylation of P proteins occurred after their being used for the encapsidation. Treatment of the infected cells with okadaic acid induced accumulation of the more acidic forms of P proteins, suggesting that heterogeneity in the full-sized P proteins is a reflection of their dynamic aspects of multiple cycles of phosphorylations and dephosphorylations in the cell. Two-D gel analyses demonstrated also that p40 was not so acidic as we expected, and implied that our previous data of apparent hyperphosphorylation of p40 was due to very frequently recycled utilization of the protein, and preformed non-labeled P proteins were also 32P-phosphorylated in a radiolabeling period and were converted to the p40.
authors.affiliation: Department of Molecular Microbiology, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan.
authors.forename: Yoshiro
authors.initials: Y
authors.lastname: Eriguchi
authors.forename: Harufusa
authors.initials: H
authors.lastname: Toriumi
authors.forename: Akihiko
authors.initials: A
authors.lastname: Kawai
mesh_terms: D002478:Cells, Cultured; D012321:DNA-Directed RNA Polymerases / Q000032:analysis* / Q000235:genetics; D015180:Electrophoresis, Gel, Two-Dimensional; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D008957:Models, Genetic; D018832:Molecular Chaperones; D019251:Nucleocapsid / Q000032:analysis / Q000145:classification; D019590:Nucleocapsid Proteins; D019319:Okadaic Acid / Q000378:metabolism; D010750:Phosphoproteins / Q000032:analysis* / Q000235:genetics / Q000378:metabolism; D010744:Phosphoric Monoester Hydrolases / Q000378:metabolism; D011820:Rabies virus / Q000201:enzymology* / Q000235:genetics; D015678:Viral Structural Proteins / Q000032:analysis* / Q000235:genetics / Q000378:metabolism
chemical_list: D018832:Molecular Chaperones; D019590:Nucleocapsid Proteins; C103961:P phosphoprotein, Rabies virus; D010750:Phosphoproteins; D015678:Viral Structural Proteins; C099601:nucleocapsid protein, Rabies virus; D019319:Okadaic Acid; D012321:DNA-Directed RNA Polymerases; D010744:Phosphoric Monoester Hydrolases