title: Transcriptional analysis of the Escherichia coli bio operon.
abstract: Using primer extension, two in vivo transcription start points (tsp) were identified for rightward transcription of the Escherichia coli biotin operon, at nucleotides (nt) +20 and +29. The strongest leftward transcript begins at +9, with a tenfold less abundant transcript starting at +3. The activity of segments cloned into promoter probe vectors locates the major leftward promoter between nt +1 and +105, as expected for the +9 tsp. Although the activity of a chromosomal operator is reduced about 300-fold by point mutation in either arm of the palindrome extending from nt -20 to +20, either a half-operator segment or a full operator bearing the same point mutation in one arm is substantially repressed when cloned into pKB2000, as though cellular location strongly affects the operator's affinity for the repressor.
authors.affiliation: Department of Biology, National Sun Yat-sen University, Kaohsiung, Taiwan.
authors.forename: D
authors.initials: D
authors.lastname: Shiuan
authors.forename: K C
authors.initials: KC
authors.lastname: Lin
authors.forename: A
authors.initials: A
authors.lastname: Campbell
mesh_terms: D001483:Base Sequence; D001710:Biotin / Q000235:genetics*; D004269:DNA, Bacterial; D004926:Escherichia coli / Q000235:genetics*; D008969:Molecular Sequence Data; D009875:Operator Regions, Genetic; D009876:Operon; D011401:Promoter Regions, Genetic; D012329:RNA, Bacterial / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics; D014158:Transcription, Genetic
chemical_list: D004269:DNA, Bacterial; D012329:RNA, Bacterial; D012333:RNA, Messenger; D001710:Biotin