title: Importance of the leader region of mRNA for translation initiation of ColE2 Rep protein.
abstract: Translation initiation of mRNA encoding the Rep protein of the ColE2 plasmid required for initiation of plasmid DNA replication is fairly efficient in Escherichia coli cells despite the absence of a canonical Shine-Dalgarno sequence. To define sequences and structural elements responsible for translation efficiency of the Rep mRNA, a series of rep-lacZalpha translational fusions bearing various mutations in the region encoding the leader region of the Rep mRNA was generated and tested for the translation activity by measuring the beta-galactosidase activity. We showed that the region rich in A and U between the stem-loop II structure and GA cluster sequence, formation of the stem-loop II structure, but not its sequence, and the region between the GA cluster sequence and initiation codon are important along with the GA cluster sequence for efficient translation of the Rep protein. The existence of these important regions in the leader region of the Rep mRNA may explain the mechanism of inhibition of the Rep protein translation by an antisense RNA (RNAI), which is complementary to the leader region.
authors.affiliation: Department of Biology, Faculty of Science, Shinshu University, Matsumoto, Nagano 390-8621, Japan.
authors.forename: Tomomi
authors.initials: T
authors.lastname: Nagase
authors.forename: Shin-ya
authors.initials: SY
authors.lastname: Nishio
authors.forename: Tateo
authors.initials: T
authors.lastname: Itoh
mesh_terms: D020121:5' Untranslated Regions / Q000235:genetics*; D003086:Bacteriocin Plasmids; D001483:Base Sequence; D018387:Codon, Initiator; D004265:DNA Helicases / Q000096:biosynthesis / Q000235:genetics*; D004268:DNA-Binding Proteins / Q000096:biosynthesis / Q000235:genetics*; D004926:Escherichia coli / Q000235:genetics* / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000096:biosynthesis / Q000235:genetics*; D015964:Gene Expression Regulation, Bacterial; D008969:Molecular Sequence Data; D009154:Mutation; D009690:Nucleic Acid Conformation; D014176:Protein Biosynthesis; D016372:RNA, Antisense / Q000235:genetics; D012329:RNA, Bacterial / Q000235:genetics; D012333:RNA, Messenger / Q000737:chemistry / Q000235:genetics*; D015534:Trans-Activators / Q000096:biosynthesis / Q000235:genetics*
chemical_list: D020121:5' Untranslated Regions; D018387:Codon, Initiator; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; D016372:RNA, Antisense; D012329:RNA, Bacterial; D012333:RNA, Messenger; D015534:Trans-Activators; C045264:replication initiator protein; D004265:DNA Helicases