DnaK-dependent ribosome biogenesis in Escherichia coli: competition for dominance between the alleles dnaK756 and dnaK+.
The Escherichia coli chaperone DnaK is vital for many cellular functions, including ribosome biogenesis at high temperature. Thus, the dnaK756-ts (lambdaR) mutant, at the non-permissive temperature, is inhibited at a late stage of ribosome assembly, yielding 21S, 32S and 45S precursor particles. This defect, unlike the lambda resistance and thermosensitivity phenotypes, is not complemented by lysogenisation with a transducing phage lambda dnaK+ bearing the wild-type dnaK gene. However this dominant phenotype becomes recessive when dnaK+ is expressed from a medium-copy-number plasmid. On the other hand, an excess of DnaK causes an unexpected dominant-lethal effect of the dnaK756 allele near non-permissive temperatures. This interplay between the dnaK+ and dnaK756 alleles supports the idea of that DnaK oligomers form in the cell.
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Institut de Biologie Physico-Chimique, UPR 9073 du CNRS, Paris, France.
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JH
D000483:Alleles; D010582:Bacteriophage lambda / Q000235:genetics*; D004926:Escherichia coli / Q000502:physiology* / Q000821:virology; D029968:Escherichia coli Proteins; D015964:Gene Expression Regulation, Bacterial; D005799:Genes, Dominant; D005804:Genes, Lethal; D005816:Genetic Complementation Test; D018840:HSP70 Heat-Shock Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D010641:Phenotype; D010957:Plasmids; D017510:Protein Folding; D012270:Ribosomes / Q000378:metabolism*
D029968:Escherichia coli Proteins; D018840:HSP70 Heat-Shock Proteins; C063842:dnaK protein, E coli