Expression of the trp operon in Φ80 trp transducing phages. Orientation of transcription and an artificial high-efficiency promotor in phage iλh+φ80pt5-2AB
article
The presence of regulatory elements belonging to the trp operon of Escherichia coli in various trp transducing phages of φ{symbol}80 has been investigated by measuring the synthesis of trp enzymes following infection of φ{symbol}80 immune bacteria. In phages which lack trp regulatory elements, synthesis of trp enzymes usually is controlled by phage regulatory elements (Franklin, 1971) but for two of these phages, iλh+φ{symbol}80pt5-2AB and φ{symbol}80pt1 it was found that the expression of trp genes is not controlled by phage regulatory elements. Our results suggest that phage iλh+φ{symbol}80pt5-AB contains an artificial promotor which presumably is located just ahead of the trpB gene. Transcription at this promotor is initiated with high efficiency as judged by the high amounts of trp enzymes synthesized in immune cells infected with this phage. The low activity of tryptophan synthetase found in immune cells infected with phage φ{symbol}80pt1 might be explained by the existence of a low-efficiency promotor within the trp operon (Morse and Yanofsky, 1968). The orientation of trp genes relative to phage genes was determined in trp transducing phages of φ{symbol}80 using the technique of DNA-RNA hybridization. The results of these experiments indicate that the trp genes in all phages tested are oriented opposite to the late genes of φ{symbol}80. © 1973 Springer-Verlag.
Chemicals/CAS: tryptophan, 6912-86-3, 73-22-3; DNA, Viral; RNA, Bacterial; RNA, Messenger; Tryptophan, 73-22-3
Chemicals/CAS: tryptophan, 6912-86-3, 73-22-3; DNA, Viral; RNA, Bacterial; RNA, Messenger; Tryptophan, 73-22-3
Topics
Bacterial RNAMessenger RNATryptophanVirus DNAColiphageGenetic transcriptionGenetic transductionHybridizationLysogenizationMicrobial geneticsOperonColiphagesDNA, ViralGenetics, MicrobialHybridization, GeneticLysogenyOperonRNA, BacterialRNA, MessengerTranscription, GeneticTransduction, GeneticTryptophan
TNO Identifier
227410
ISSN
00268925
Source
MGG Molecular & General Genetics, 120(1), pp. 55-68.
Publisher
Springer-Verlag
Pages
55-68
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