Biomaterial Database

[Dependence of threonine operon expression on the relA gene allelic state and the level of guanosine tetraphosphate in E. coli]. 1981

B V Perel'man, and R S Shakulov

The expression of threonine operon in Rel+ and Rel- E. coli cells was studied at the transcriptional level. The rel+ genotype and the lack of a specific amino acid--threonine--are necessary for the stimulation of threonine operon transcription. Under these conditions the RNA fraction, which is thr-mRNA, is increased 2-fold. The lack of arginine or histidine in Rel+ strain does not lead to derepression of the threonine operon. It is shown that in a cell-free system 0.1 mM ppGpp stimulate the synthesis of thr-mRNA on phage DNA lambda dthr and plasmid DNA PYN1107, containing total threonine operon 1.5--2-fold. It is assumed that ppGpp stimulates the initiation of transcription. Studies on the strain carrying spoT- mutation, which significantly lowers the rate of ppGpp degradation and results in suppression of rel- phenotype, revealed positive correlation between the intracellular level of ppGpp and the thr-mRNA fraction in the total transcript.

UI	MeSH Term	Description	Entries
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D009154	Mutation	Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.	Mutations
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
D010957	Plasmids	Extrachromosomal, usually CIRCULAR DNA molecules that are self-replicating and transferable from one organism to another. They are found in a variety of bacterial, archaeal, fungal, algal, and plant species. They are used in GENETIC ENGINEERING as CLONING VECTORS.	Episomes,Episome,Plasmid
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
D006150	Guanine Nucleotides		Guanine Nucleotide,Guanosine Phosphates,Nucleotide, Guanine,Nucleotides, Guanine,Phosphates, Guanosine
D006159	Guanosine Tetraphosphate	Guanosine 5'-diphosphate 2'(3')-diphosphate. A guanine nucleotide containing four phosphate groups. Two phosphate groups are esterified to the sugar moiety in the 5' position and the other two in the 2' or 3' position. This nucleotide serves as a messenger to turn off the synthesis of ribosomal RNA when amino acids are not available for protein synthesis. Synonym: magic spot I.	Alarmone ppGpp,Bacterial Magic Spot ppGpp,Guanosine 5'-(trihydrogen diphosphate), mono(trihydrogen diphosphate) (ester),Guanosine 5'-diphosphate 2'(3')-diphosphate,ppGpp,Guanosine 3'-Diphosphate 5'-Diphosphate,Guanosine 5'-Diphosphate 3'-Diphosphate,3'-Diphosphate 5'-Diphosphate, Guanosine,5'-Diphosphate 3'-Diphosphate, Guanosine,Guanosine 3' Diphosphate 5' Diphosphate,Guanosine 5' Diphosphate 3' Diphosphate,Tetraphosphate, Guanosine,ppGpp, Alarmone
D000483	Alleles	Variant forms of the same gene, occupying the same locus on homologous CHROMOSOMES, and governing the variants in production of the same gene product.	Allelomorphs,Allele,Allelomorph
D013912	Threonine	An essential amino acid occurring naturally in the L-form, which is the active form. It is found in eggs, milk, gelatin, and other proteins.	L-Threonine,L Threonine
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