Disease relevance of spoT

• The global transcriptional regulator (p)ppGpp (guanosine-3'-diphosphate-5'-triphosphate and guanosine-3',5'-bisphosphate, collectively) produced by the relA and spoT genes in Escherichia coli allows bacteria to adapt to different environmental stresses [1].
• We find that high levels of ppGpp in E. coli, resulting from amino acid starvation or from spoT mutation, activate rather than repress the transcription of the mycoplasma rrnA operon [2].
• The Mycobacterium tuberculosis relA and spoT homologue, when induced in M. smegmatis, also resulted in the overproduction of ppGpp with a change in the bacterium's growth characteristics [3].

High impact information on spoT

• Colonies displaying an increased growth rate were isolated, and mapping of a suppressor mutation revealed a base pair substitution in the spoT gene [4].
• These two sets of isogenic pairs of rel+ and rel minus strains are commonly used in the study of rel gene function; however, NF161 is a mutant in the spoT gene whose product may be responsible for the degradation of ppGpp [5].
• spoT-dependent accumulation of guanosine tetraphosphate in response to fatty acid starvation in Escherichia coli [6].
• The activation was dependent on relA and spoT, which encode enzymes for the synthesis and degradation of ppGpp, and on dksA, which encodes an RNA polymerase accessory protein required for the stringent response [7].
• The results suggest that PSII is unstable with an average functional lifetime of 40 seconds or less, and that its activity is generated during or shortly after spoT mRNA translation in response to the availability of amino acids [8].

Chemical compound and disease context of spoT

• Although the source of (p)ppGpp synthesis during glucose exhaustion remains to be determined, these findings reinforce the idea entertained previously that rel(Seq) fulfils functions that reside separately in the paralogous reL4 and spoT genes of Escherichia coli [9].
• Uncharged tRNA inhibits guanosine 3',5'-bis (diphosphate) 3'-pyrophosphohydrolase [ppGppase], the spoT gene product, from Escherichia coli [10].
• Mutation spoT of Escherichia coli increases expression of the histidine operon deleted for the attenuator [11].
• Expression of an NH2-terminal portion of Cr-RSH containing the putative ppGpp synthase domain in a relA, spoT double mutant of Escherichia coli complemented the growth deficits of the mutant cells [12].

Biological context of spoT

• The genome of Borrelia burgdorferi encodes a single chromosomal rel gene (BB0198) (B. burgdorferi rel [rel(Bbu)]) homologous to relA and spoT of E. coli [1].
• The rpoZ gene for the omega subunit of Escherichia coli RNA polymerase constitutes single operon with the spoT gene, which is responsible for the maintenance of stringent response under nutrient starvation conditions [13].
• The chance of isolating spoT mutants, which can be selected with a similar procedure, was decreased by selecting in the presence of a multicopy plasmid that carries the wild-type spoT gene [14].
• There was no apparent correlation between the ability to control translation and the genotypes of these strains at the relA, relX, or spoT loci [15].
• The restoration of viability of fatty-acid-starved spoT mutant cells through the addition of exogenous catalase suggested that the observed light-dependent lethal effect was, at least in part, caused by UV-imposed oxidative stress [16].

Associations of spoT with chemical compounds

• The breakdown of guanosine 5'-diphosphate, 3'-diphosphate (ppGpp) into GDP and PPi is catalyzed by a Mn2+-dependent 3'-pyrophosphohydrolase, the translation product of the spoT gene [17].
• This result indicates that spoT also participates in pppGpp degradation [18].
• Effects of the spoT and relA mutation on the synthesis and accumulation of ppGpp and RNA during glucose starvation [19].

References