Identification of the regulatory sequence of anaerobically expressed locus aeg-46.5.
A newly identified anaerobically expressed locus, aeg-46.5, which is located at min 46.5 on Escherichia coli linkage map, was cloned and analyzed. The phenotype of this gene was studied by using a lacZ operon fusion. aeg-46.5 is induced anaerobically in the presence of nitrate in wild-type and narL cells. It is repressed by the narL gene product, as it showed derepressed anaerobic expression in narL mutant cells. We postulate that aeg-46.5 is subject to multiple regulatory systems, activation as a result of anaerobiosis, narL-independent nitrate-dependent activation, and narL-mediated repression. The regulatory region of aeg-46.5 was identified. A 304-bp DNA sequence which includes the regulatory elements was obtained, and the 5' end of aeg-46.5 mRNA was identified. It was verified that the anaerobic regulation of aeg-46.5 expression is controlled on the transcriptional level. Computer analysis predicted possible control sites for the NarL and FNR proteins. The proposed NarL site was found in a perfect-symmetry element. The aeg-46.5 regulatory elements are adjacent to, but divergent from, those of the eco gene.
Choe
M
M
Department of Biochemistry, University of Wisconsin, Madison 53706.
Reznikoff
W S
WS
D000595:Amino Acid Sequence; D000693:Anaerobiosis; D001426:Bacterial Proteins / Q000235:genetics; D001483:Base Sequence; D003001:Cloning, Molecular; D004269:DNA, Bacterial / Q000235:genetics; D004268:DNA-Binding Proteins; D004926:Escherichia coli / Q000235:genetics*; D029968:Escherichia coli Proteins; D015964:Gene Expression Regulation, Bacterial; D008969:Molecular Sequence Data; D012333:RNA, Messenger / Q000235:genetics; D012045:Regulatory Sequences, Nucleic Acid; D012097:Repressor Proteins / Q000235:genetics; D017384:Sequence Deletion; D014158:Transcription, Genetic
D001426:Bacterial Proteins; D004269:DNA, Bacterial; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; D012333:RNA, Messenger; D012097:Repressor Proteins; C069780:NarL protein, E coli