title: Translation of the rat LINE bicistronic RNAs in vitro involves ribosomal reinitiation instead of frameshifting.
abstract: The genomic structure of the rat LINE (L1Rn) DNA element contains two overlapping open reading frames (ORFs) and apparently has a potential to code for a DNA/RNA-binding protein (in ORF1) and a reverse transcriptase (in ORF2). We have characterized a 1,630-bp L1Rn cDNA clone encompassing the overlapping ORFs and a 600-bp genomic fragment derived from a full-length L1Rn member and containing the beginning of ORF1. These DNAs were used to restore in part the ORF1-ORF2 organization of L1Rn after being cloned into the pSP65 vector under the control of SP6 polymerase promoter. To test whether L1Rn ORF1 and ORF2 are expressed as a fusion protein, a series of capped RNAs with progressive truncations containing one or both ORFs were prepared and translated in the rabbit reticulocyte lysate. Our analysis indicates that the expression of a putative reverse transcriptase-encoded L1Rn ORF2 in vitro is regulated by reinitiation or internal initiation of translation but not by ribosomal frameshifting.
authors.affiliation: Laboratory of Molecular Genetics, Institute of Chemical Physics and Biophysics, Tartu, Estonia.
authors.forename: H
authors.initials: H
authors.lastname: Ilves
authors.forename: O
authors.initials: O
authors.lastname: Kahre
authors.forename: M
authors.initials: M
authors.lastname: Speek
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D004247:DNA; D004251:DNA Transposable Elements; D004268:DNA-Binding Proteins / Q000235:genetics*; D008969:Molecular Sequence Data; D016366:Open Reading Frames / Q000235:genetics; D014176:Protein Biosynthesis; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000235:genetics*; D012194:RNA-Directed DNA Polymerase / Q000235:genetics*; D051381:Rats; D012091:Repetitive Sequences, Nucleic Acid; D012270:Ribosomes / Q000378:metabolism*
chemical_list: D004251:DNA Transposable Elements; D004268:DNA-Binding Proteins; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D004247:DNA; D012194:RNA-Directed DNA Polymerase