Biomaterial Database

Punctuation of transcription in vitro of the tryptophan operon of Escherichia coli. A novel type of control of transcription. 1975

H Pannekoek, and W J Brammar, and P H Pouwels

Medical Biological Laboratory TNO, Rijswijk, The Netherlands.

RNA transcribed in vitro from DNA of a tryptophan (trp) transducing strain of bacteriophage phi80 which contains the trp regulatory elements consists of a polycistronic messenger transcribed from the structural genes, and possibly the regulatory region, and a separate RNA species (called trp regRNA) which is transcribed from the regulatory region. This conclusion is based on hybridization experiments with trp RNA synthesized in vitro and the separate DNA strands of trp transducing strains of lambda with and without the trp regulatory elements. The length of trp regRNA determined by filtration on Sephadex G-200 is 110-180 nucleotides. From the amount and the length of trp regRNA we have calculated that 8-20 copies of trp regRNA are synthesized per copy of polycistronic trp mRNA. We conclude that during transcription of the trp operon RNA polymerase frequently is rejected at a specific site ahead of the first structural gene, trpE. The termination factor Rho is not involved in this process. A different protein fraction, which specifically stimulates the synthesis of trp enzymes in an in vitro protein-synthesizing system (Pouwels and Van Rotterdam, 1975), was found to antagonize the abortive synthesis of trp mRNA. A model is proposed for the control of transcription of the trp genes, which operates through a mechanism of punctuation of RNA synthesis at a specific site on the DNA template and anti-termination of RNA synthesis by means of a positive control factor.

UI	MeSH Term	Description	Entries
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D009693	Nucleic Acid Hybridization	Widely used technique which exploits the ability of complementary sequences in single-stranded DNAs or RNAs to pair with each other to form a double helix. Hybridization can take place between two complimentary DNA sequences, between a single-stranded DNA and a complementary RNA, or between two RNA sequences. The technique is used to detect and isolate specific sequences, measure homology, or define other characteristics of one or both strands. (Kendrew, Encyclopedia of Molecular Biology, 1994, p503)	Genomic Hybridization,Acid Hybridization, Nucleic,Acid Hybridizations, Nucleic,Genomic Hybridizations,Hybridization, Genomic,Hybridization, Nucleic Acid,Hybridizations, Genomic,Hybridizations, Nucleic Acid,Nucleic Acid Hybridizations
D009876	Operon	In bacteria, a group of metabolically related genes, with a common promoter, whose transcription into a single polycistronic MESSENGER RNA is under the control of an OPERATOR REGION.	Operons
D012045	Regulatory Sequences, Nucleic Acid	Nucleic acid sequences involved in regulating the expression of genes.	Nucleic Acid Regulatory Sequences,Regulatory Regions, Nucleic Acid (Genetics),Region, Regulatory,Regions, Regulatory,Regulator Regions, Nucleic Acid,Regulatory Region,Regulatory Regions
D003090	Coliphages	Viruses whose host is Escherichia coli.	Escherichia coli Phages,Coliphage,Escherichia coli Phage,Phage, Escherichia coli,Phages, Escherichia coli
D004279	DNA, Viral	Deoxyribonucleic acid that makes up the genetic material of viruses.	Viral DNA
D004926	Escherichia coli	A species of gram-negative, facultatively anaerobic, rod-shaped bacteria (GRAM-NEGATIVE FACULTATIVELY ANAEROBIC RODS) commonly found in the lower part of the intestine of warm-blooded animals. It is usually nonpathogenic, but some strains are known to produce DIARRHEA and pyogenic infections. Pathogenic strains (virotypes) are classified by their specific pathogenic mechanisms such as toxins (ENTEROTOXIGENIC ESCHERICHIA COLI), etc.	Alkalescens-Dispar Group,Bacillus coli,Bacterium coli,Bacterium coli commune,Diffusely Adherent Escherichia coli,E coli,EAggEC,Enteroaggregative Escherichia coli,Enterococcus coli,Diffusely Adherent E. coli,Enteroaggregative E. coli,Enteroinvasive E. coli,Enteroinvasive Escherichia coli
D012234	Rho Factor	A protein which effects termination of RNA synthesis during the genetic transcription process by dissociating the ternary transcription complex RNA;-RNA POLYMERASE DNA at the termination of a gene.	E Coli Transcription Termination Factor,Factor, Rho
D012321	DNA-Directed RNA Polymerases	Enzymes that catalyze DNA template-directed extension of the 3'-end of an RNA strand one nucleotide at a time. They can initiate a chain de novo. In eukaryotes, three forms of the enzyme have been distinguished on the basis of sensitivity to alpha-amanitin, and the type of RNA synthesized. (From Enzyme Nomenclature, 1992).	DNA-Dependent RNA Polymerases,RNA Polymerases,Transcriptases,DNA-Directed RNA Polymerase,RNA Polymerase,Transcriptase,DNA Dependent RNA Polymerases,DNA Directed RNA Polymerase,DNA Directed RNA Polymerases,Polymerase, DNA-Directed RNA,Polymerase, RNA,Polymerases, DNA-Dependent RNA,Polymerases, DNA-Directed RNA,Polymerases, RNA,RNA Polymerase, DNA-Directed,RNA Polymerases, DNA-Dependent,RNA Polymerases, DNA-Directed
D012329	RNA, Bacterial	Ribonucleic acid in bacteria having regulatory and catalytic roles as well as involvement in protein synthesis.	Bacterial RNA