title: Structural and functional analysis of cloned deoxyribonucleic acid containing the trpR-thr region of the Escherichia coli chromosome.
abstract: Specialized transducing phages containing the thr-trpR region of the Escherichia coli chromosome were derived from a strain with lambda prophage inserted in thr. Cloning of segments of the chromosomal deoxyribonucleic acid of one such lambda thr + trpR+ phage in various plasmid vectors established that a 1.3-kilobase BamHI fragment carried trpR+ intact. Strains with a multicopy plasmid vector containing the BamHI insert produced 20-fold-higher levels of trp aporepressor than did the wild-type strain of Escherichia coli. Similarly, induction of lambda thr + trpR+ lysogens resulted in increased aporepressor levels. The 1.3-kilobase trpR+ BamHI fragment was inserted in either orientation downstream from lambda pLN in a plasmid vector in which transcription from lambda pL was under the control of a temperature-sensitive lambda repressor. Induction established the orientation of transcription of trpR and led to the production of 100-fold-increased levels of trp aporepressor. A presumptive 23,500-dalton trpR+ polypeptide was detected by using lambda pLNtrpR+ plasmid deoxyribonucleic acid in a cell-free transcription-translation system.
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics*; D010582:Bacteriophage lambda / Q000235:genetics; D003001:Cloning, Molecular; D004269:DNA, Bacterial / Q000235:genetics*; D004274:DNA, Recombinant; D004926:Escherichia coli / Q000235:genetics*; D005809:Genes, Regulator; D010957:Plasmids; D012097:Repressor Proteins / Q000096:biosynthesis / Q000235:genetics*; D014157:Transcription Factors / Q000235:genetics*; D014158:Transcription, Genetic; D014364:Tryptophan / Q000096:biosynthesis
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D004274:DNA, Recombinant; D012097:Repressor Proteins; D014157:Transcription Factors; D014364:Tryptophan