title: Poly (rC) binding protein 2 forms a ternary complex with the 5'-terminal sequences of poliovirus RNA and the viral 3CD proteinase.
abstract: Poly(rC) binding protein 2 (PCBP2) forms a specific ribonucleoprotein (RNP) complex with the 5'-terminal sequences of poliovirus genomic RNA, as determined by electrophoretic mobility shift assay. Mutational analysis showed that binding requires the wild-type nucleotide sequence at positions 20-25. This sequence is predicted to localize to a specific stem-loop within a cloverleaf-like secondary structure element at the 5'-terminus of the viral RNA. Addition of purified poliovirus 3CD to the PCBP2/RNA binding reaction results in the formation of a ternary complex, whose electrophoretic mobility is further retarded. These properties are consistent with those described for the unidentified cellular protein in the RNP complex described by Andino et al. (Andino R, Rieckhof GE, Achacoso PL, Baltimore D, 1993, EMBO J 12:3587-3598). Dicistronic RNAs containing mutations in the 5' cloverleaf-like structure of poliovirus that abate PCBP2 binding show a decrease in RNA replication and translation of gene products directed by the poliovirus 5' noncoding region in vitro, suggesting that the interaction of PCBP2 with these sequences performs a dual role in the virus life cycle by facilitating both viral protein synthesis and initiation of viral RNA synthesis.
authors.affiliation: Department of Microbiology and Molecular Genetics, College of Medicine, University of California, Irvine 92697, USA.
authors.forename: T B
authors.initials: TB
authors.lastname: Parsley
authors.forename: J S
authors.initials: JS
authors.lastname: Towner
authors.forename: L B
authors.initials: LB
authors.lastname: Blyn
authors.forename: E
authors.initials: E
authors.lastname: Ehrenfeld
authors.forename: B L
authors.initials: BL
authors.lastname: Semler
mesh_terms: D000086042:3C Viral Proteases; D001483:Base Sequence; D003546:Cysteine Endopeptidases / Q000378:metabolism*; D004268:DNA-Binding Proteins; D004591:Electrophoresis, Polyacrylamide Gel; D006367:HeLa Cells; D034441:Heterogeneous-Nuclear Ribonucleoproteins; D006801:Humans; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009690:Nucleic Acid Conformation; D017955:Poliovirus / Q000201:enzymology / Q000235:genetics*; D014176:Protein Biosynthesis; D015347:RNA Probes; D012367:RNA, Viral / Q000737:chemistry / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011994:Recombinant Proteins / Q000378:metabolism; D012261:Ribonucleoproteins / Q000737:chemistry; D014157:Transcription Factors; D014170:Transformation, Genetic; D014764:Viral Proteins
chemical_list: D004268:DNA-Binding Proteins; D034441:Heterogeneous-Nuclear Ribonucleoproteins; C501903:PCBP2 protein, human; D015347:RNA Probes; D012367:RNA, Viral; D016601:RNA-Binding Proteins; D011994:Recombinant Proteins; D012261:Ribonucleoproteins; D014157:Transcription Factors; D014764:Viral Proteins; D003546:Cysteine Endopeptidases; D000086042:3C Viral Proteases