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Title: Multiple isoelectric forms of poliovirus RNA-dependent RNA polymerase: Evidence for phosphorylation

Poliovirus-specific RNA-dependent RNA polymerase (3Dpol) was purified to apparent homogeneity. A single polypeptide of an apparent molecular weight of 63,000 catalyzes the synthesis of dimeric and monomeric RNA products in response to the poliovirion RNA template. Analysis of purified 3Dpol by two-dimensional electrophoresis showed multiple forms of 3Dpol, suggesting posttranslational modification of the protein in virus-infected cells. The two major forms of 3Dpol appear to have approximate pI values of 7.1 and 7.4. Incubation of purified 3Dpol with calf intestinal phosphatase resulted in almost complete disappearance of the pI 7.1 form and a concomitant increase in the intensity of the pI 7.4 form of 3Dpol. Addition of 32P-labeled Pi during infection of HeLa cells with poliovirus resulted in specific labeling of 3Dpol and 3CD, a viral protein which contains the entire 3Dpol sequence. Both 3Dpol and 3CD appear to be phosphorylated at serine residues. Ribosomal salt washes prepared from both mock- and poliovirus-infected cells contain phosphatases capable of dephosphorylating quantitatively the phosphorylated form (pI 7.1) of 3Dpol.
Authors:
;  [1]
  1. (Univ. of California, Los Angeles (USA))
Publication Date:
OSTI Identifier:
5228659
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Virology; (USA); Journal Volume: 63:11
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES; RNA POLYMERASES; PHOSPHORYLATION; AMINO ACID SEQUENCE; HELA CELLS; MAN; MOLECULAR WEIGHT; PHOSPHATASES; PHOSPHORUS 32; POLIO VIRUS; TRACER TECHNIQUES; TRANSCRIPTION; TWO-DIMENSIONAL ELECTROPHORESIS; ANIMALS; BETA DECAY RADIOISOTOPES; BETA-MINUS DECAY RADIOISOTOPES; CHEMICAL REACTIONS; DAYS LIVING RADIOISOTOPES; ELECTROPHORESIS; ENZYMES; ESTERASES; HYDROLASES; ISOTOPE APPLICATIONS; ISOTOPES; LIGHT NUCLEI; MAMMALS; MICROORGANISMS; MOLECULAR STRUCTURE; NUCLEI; NUCLEOTIDYLTRANSFERASES; ODD-ODD NUCLEI; PARASITES; PHOSPHORUS ISOTOPES; PHOSPHORUS-GROUP TRANSFERASES; POLYMERASES; PRIMATES; RADIOISOTOPES; TRANSFERASES; VERTEBRATES; VIRUSES 550201* -- Biochemistry-- Tracer Techniques