Frameshifting in the expression of the E. coli trpR gene occurs by the bypassing of a segment of its coding sequence.
The E. coli trpR gene encodes the 108 amino acid long trp repressor. We have previously shown that a +1 frameshifting event occurs during the expression of trpR. Here we show that the transition from the 0 to the +1 frame of trpR occurs by the bypassing of a 55 nt long segment of the trpR+1-lacZ mRNA. This bypassing event is not pretranslational, and it probably takes place during translation. Two adjacent elements are required: a specific sequence of trpR, which must be preceded by a nonspecific 5' end longer than 10 translatable codons. Unique to trpR-lacZ bypassing is that the 55 nt long region must be translated in frame 0 to enable bypassing into the +1 frame. Translational bypassing as a newly discovered mechanism of gene expression is discussed, and the possible existence of translational introns is suggested.
Benhar
I
I
Department of Molecular Biology, Hebrew University, Hadassah Medical School, Jerusalem, Israel.
Engelberg-Kulka
H
H
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D001483:Base Sequence; D003062:Codon; D004269:DNA, Bacterial; D004926:Escherichia coli / Q000235:genetics* / Q000378:metabolism; D005091:Exons; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D007438:Introns; D007763:Lac Operon; D008969:Molecular Sequence Data; D014176:Protein Biosynthesis; D012097:Repressor Proteins / Q000235:genetics* / Q000378:metabolism; D015183:Restriction Mapping; D014364:Tryptophan / Q000378:metabolism*; D029968:Escherichia coli Proteins
D001426:Bacterial Proteins; D003062:Codon; D004269:DNA, Bacterial; D012097:Repressor Proteins; D014364:Tryptophan; C027190:TRPR protein, E coli; D029968:Escherichia coli Proteins