title: Ribosomal frameshifting during translation of measles virus P protein mRNA is capable of directing synthesis of a unique protein.
abstract: Members of the Paramyxoviridae family utilize a variety of different strategies to increase coding capacity within their P cistrons. Translation initiation at alternative 5'-proximal AUG codons is used by measles virus (MV) to express the virus-specific P and C proteins from overlapping reading frames on their mRNAs. Additional species of mRNAs are transcribed from the MV P cistron by the insertion of extra nontemplated G residues at a specific site within the P transcript. Addition of only a single nontemplated G residue results in the expression of the V protein, which contains a unique carboxyl terminus. We have used an Escherichia coli system to express MV P cistron-related mRNAs and proteins. We have found that ribosomal frameshifting on the MV P protein mRNA is capable of generating a previously unrecognized P cistron-encoded protein that we have designated R. Some ribosomes which have initiated translation of the P protein mRNA use the sequence TCC CCG AG (24 nucleotides upstream of the V protein stop codon) to slip into the -1 reading frame, thus translating the sequence as TC CCC GAG. The resulting R protein terminates five codons downstream of the frameshift site at the V protein stop codon. We have gone on to use a chloramphenicol acetyltransferase reporter system to demonstrate that this MV-specific sequence is capable of directing frameshifting during in vivo translation in eukaryotic cells. Analysis of immunoprecipitated proteins from MV-infected cells by two-dimensional gel electrophoresis allowed detection of a protein species consistent with R protein in MV-infected cells. Quantitation of this protein species allowed a rough estimation of frameshift frequency of approximately 1.8%. Significant stimulation of ribosomal frameshift frequency at this locus of the MV P mRNA was mediated by a downstream stimulator element which, although not yet fully defined, appeared to be neither a conventional stem-loop nor an RNA pseudoknot structure.
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015153:Blotting, Western; D002522:Chlorocebus aethiops; D017931:DNA Primers; D018965:Frameshifting, Ribosomal; D005814:Genes, Viral; D005982:Glutathione Transferase / Q000096:biosynthesis / Q000302:isolation & purification; D008459:Measles virus / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D016366:Open Reading Frames; D010750:Phosphoproteins; D010957:Plasmids; D016133:Polymerase Chain Reaction; D014176:Protein Biosynthesis; D012333:RNA, Messenger / Q000737:chemistry / Q000378:metabolism*; D012367:RNA, Viral / Q000737:chemistry / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis / Q000302:isolation & purification; D017384:Sequence Deletion; D014162:Transfection; D014709:Vero Cells; D014764:Viral Proteins / Q000096:biosynthesis* / Q000302:isolation & purification; D015678:Viral Structural Proteins / Q000235:genetics
chemical_list: D017931:DNA Primers; C055859:P protein, Sendai virus; D010750:Phosphoproteins; D012333:RNA, Messenger; D012367:RNA, Viral; D011993:Recombinant Fusion Proteins; D014764:Viral Proteins; D015678:Viral Structural Proteins; D005982:Glutathione Transferase