Induction of the heat shock regulon in response to increased mistranslation requires oxidative modification of the malformed proteins.
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.
Fredriksson
Asa
A
Department of Cell and Molecular Biology - Microbiology, Göteborg University, Medicinaregatan 9C, 413 90 Göteborg, Sweden.
Ballesteros
Manuel
M
Dukan
Sam
S
Nyström
Thomas
T
D018834:Chaperonin 60 / Q000235:genetics / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D050956:HSP40 Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism; D018840:HSP70 Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism; D006360:Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism; D018869:Heat-Shock Response / Q000235:genetics*; D009154:Mutation; D010084:Oxidation-Reduction; D010100:Oxygen / Q000378:metabolism; D014176:Protein Biosynthesis; D011487:Protein Conformation; D018085:Regulon; D015533:Transcriptional Activation
D018834:Chaperonin 60; C494635:DnaJ protein, E coli; D029968:Escherichia coli Proteins; D050956:HSP40 Heat-Shock Proteins; D018840:HSP70 Heat-Shock Proteins; D006360:Heat-Shock Proteins; C063842:dnaK protein, E coli; D010100:Oxygen