Biomaterial Database

Positive control of gene expression in procaryotes. 1992

R E Drew

Department of Biochemistry and Molecular Biology, University College London, England.

In procaryotes three types of control network are involved with the regulation of gene expression: global control networks, operon/single gene specific regulation and temporal control systems. The mechanisms used for positive control include the use of new components of the transcription apparatus such as new RNA polymerases and sigma factors, the use of activator proteins and the use of transcription antitermination systems. For the second two mechanisms, secondary negative control systems may also operate to regulate the activity of activator proteins and transcription antitermination factors. Thus, only very rarely is regulation achieved by just a simple positive control system. Positive control circuits allow tight regulation of gene expression that is fail-safe, in that most mutant changes will lead to the system becoming non-inducible rather than lead to constitutive gene expression.

UI	MeSH Term	Description	Entries
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
D014158	Transcription, Genetic	The biosynthesis of RNA carried out on a template of DNA. The biosynthesis of DNA from an RNA template is called REVERSE TRANSCRIPTION.	Genetic Transcription
D015964	Gene Expression Regulation, Bacterial	Any of the processes by which cytoplasmic or intercellular factors influence the differential control of gene action in bacteria.	Bacterial Gene Expression Regulation,Regulation of Gene Expression, Bacterial,Regulation, Gene Expression, Bacterial