Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0038187 (starvation)
 24,951 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

It has previously been shown that the phenylalanine codon UUC encoding residue 8 of the Escherichia coli argI gene product, ornithine transcarbamylase, is misread as leucine at a high frequency during phenylalanine starvation. However, no misreading of the UUU encoding residue 3 was observed under these conditions. Using oligonucleotide-directed, site-specific mutagenesis, we have constructed mutants where these codons have been changed. Using these mutant argI genes we see a high level of mistranslation at position 8 during phenylalanine starvation whether the codon is UUU or UUC. With either codon at position 3 we see no leucine substitution. We also constructed a gene with a leucine codon at position 3. The product of this latter mutated gene is stable and active, indicating that preferential turnover of mistranslated protein is not obscuring an otherwise high rate of misreading. This would seem to indicate that it is the context rather than the particular phenylalanine codon which is important in determining these misreading levels.
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PMID:Context specific misreading of phenylalanine codons. 268 41

During asparagine starvation the frequency of lysine for asparagine substitutions increases to levels that enable one to isolate and sequence mistranslated protein. We have used site-directed mutagenesis to construct a series of derivatives of the gene encoding the coat protein of the bacteriophage MS2. The mutant set constructed has either AAU or AAC as codon three in the gene with each possible adjoining 3' base. Lysine incorporation in coat protein encoded by these genes shows that AAU is misread from 4- to 9-fold more frequently than AAC with any 3' context. Although in some cases context effects of approximately 2-fold were noted, there seems to be no simple hypothesis to explain them.
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PMID:Missense misreading of asparagine codons as a function of codon identity and context. 311 58

Amino acid starvation of a variety of different types of cells has been reported to induce protein degradation and also specific mistranslation. For certain amino acid starvations, the mistranslated protein, which contains specific amino acid substitutions, can be separated and quantified by two-dimensional polyacrylamide gel electrophoresis. In this paper, I show that this specifically mistranslated protein, made during amino acid starvation, does not seem to be preferentially degraded during continued starvation or renewed growth. Specifically mistranslated ribosomal protein is also assembled into ribosomes in the same proportion that it is made. These results imply that the amino acid substitutions apparently made (lysine for asparagine or glutamine or histidine) do not lead to proteins recognized as grossly "abnormal" by the cell's proteolysis systems.
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PMID:Mistranslated protein in Escherichia coli. 702 69

The Escherichia coli rpsD12 allele, which reduces translational fidelity and elevates expression of heat shock protein (Hsp) genes, only enhanced Hsp gene expression in the presence of oxygen. Similarly, the rpsL141 allele, which reduces mistranslation and Hsp gene expression, failed to affect the Hsp regulon in cells grown anaerobically. Increased production of Hsps in response to starvation is associated with increased mistranslation and was demonstrated to likewise require the presence of oxygen. Thus, mistranslation triggered by starvation or mutations in the accuracy centre of the ribosome appear to elevate Hsp gene expression via an oxidative modification of mistranslated proteins. In contrast, Hsp gene induction during temperature upshifts was independent of oxygen availability. The data further suggest that it is the oxidative modification of mistranslated DnaK substrates rather than oxidation of DnaK itself that triggers Hsp gene expression upon starvation.
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PMID:Induction of the heat shock regulon in response to increased mistranslation requires oxidative modification of the malformed proteins. 1635 40