Visualizing high error levels during gene expression in living bacterial cells.
To monitor inaccuracy in gene expression in living cells, we designed an experimental system in the bacterium Bacillus subtilis whereby spontaneous errors can be visualized and quantified at a single-cell level. Our strategy was to introduce mutations into a chromosomally encoded gfp allele, such that errors in protein production are reported in real time by the formation of fluorescent GFP molecules. The data reveal that the amount of errors can greatly exceed previous estimates, and that the error rate increases dramatically at lower temperatures and during stationary phase. Furthermore, we demonstrate that when facing an antibiotic threat, an increase in error level is sufficient to allow survival of bacteria carrying a mutated antibiotic-resistance gene. We propose that bacterial gene expression is error prone, frequently yielding protein molecules that differ slightly from the sequence specified by their DNA, thus generating a cellular reservoir of nonidentical protein molecules. This variation may be a key factor in increasing bacterial fitness, expanding the capability of an isogenic population to face environmental challenges.
Meyerovich
Mor
M
Department of Microbiology and Molecular Genetics, Institute for Medical Research, Israel-Canada, Hebrew University-Hadassah Medical School, Hebrew University of Jerusalem, 91120 Jerusalem, Israel.
Mamou
Gideon
G
Ben-Yehuda
Sigal
S
D000483:Alleles; D001412:Bacillus subtilis / Q000235:genetics*; D001419:Bacteria / Q000235:genetics*; D002470:Cell Survival; D002701:Chloramphenicol / Q000494:pharmacology; D003062:Codon; D004247:DNA / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D014644:Genetic Variation; D049452:Green Fluorescent Proteins / Q000378:metabolism; D008856:Microscopy, Fluorescence / Q000379:methods; D008954:Models, Biological; D009154:Mutation; D014176:Protein Biosynthesis; D015203:Reproducibility of Results
D003062:Codon; D049452:Green Fluorescent Proteins; D002701:Chloramphenicol; D004247:DNA