title: Reported translational bypass in a trpR'-lacZ' fusion is accounted for by unusual initiation and +1 frameshifting.
abstract: I. Benhar and H. Engelberg-Kulka reported that a 55 nucleotide translational bypass occurs in decoding a fusion of the Escherichia coli tryptophan repressor, trpR, and lacZ genes. The start of the bypass occurred in the trpR gene and coding resumed in the lacZ gene. It was considered that bypassing likely occurred in expression of trpR itself to produce an additional 10 kDa product which may be biologically important. We report here that bypass is undetectable in the same and related trpR'-lacZ' fusions. The beta-galactosidase activity derived from the fusions is accounted for by unusual internal initiation and +1 frameshifting, both of which occur in the lacZ part of the fusion. The 10 kDa product reportedly encoded by the trpR gene was not detectable to a level of 1% of the full-length 12 kDa tryptophan repressor product, at least when expressed from a T7 promoter.
authors.affiliation: Howard Hughes Medical Institute, University of Utah, Salt Lake City, UT 84112, USA.
authors.forename: N M
authors.initials: NM
authors.lastname: Wills
authors.forename: J A
authors.initials: JA
authors.lastname: Ingram
authors.forename: R F
authors.initials: RF
authors.lastname: Gesteland
authors.forename: J F
authors.initials: JF
authors.lastname: Atkins
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins; D001483:Base Sequence; D004926:Escherichia coli / Q000235:genetics; D018965:Frameshifting, Ribosomal; D005982:Glutathione Transferase / Q000235:genetics; D008969:Molecular Sequence Data; D010442:Peptide Chain Initiation, Translational; D011993:Recombinant Fusion Proteins / Q000235:genetics; D012097:Repressor Proteins / Q000235:genetics*; D001616:beta-Galactosidase / Q000235:genetics*; D029968:Escherichia coli Proteins
chemical_list: D001426:Bacterial Proteins; D005982:Glutathione Transferase; D011993:Recombinant Fusion Proteins; D012097:Repressor Proteins; D001616:beta-Galactosidase; C027190:TRPR protein, E coli; D029968:Escherichia coli Proteins