title: A Comparison of the Costs and Benefits of Bacterial Gene Expression.
abstract: To study how a bacterium allocates its resources, we compared the costs and benefits of most (86%) of the proteins in Escherichia coli K-12 during growth in minimal glucose medium. The cost or investment in each protein was estimated from ribosomal profiling data, and the benefit of each protein was measured by assaying a library of transposon mutants. We found that proteins that are important for fitness are usually highly expressed, and 95% of these proteins are expressed at above 13 parts per million (ppm). Conversely, proteins that do not measurably benefit the host (with a benefit of less than 5% per generation) tend to be weakly expressed, with a median expression of 13 ppm. In aggregate, genes with no detectable benefit account for 31% of protein production, or about 22% if we correct for genetic redundancy. Although some of the apparently unnecessary expression could have subtle benefits in minimal glucose medium, the majority of the burden is due to genes that are important in other conditions. We propose that at least 13% of the cell's protein is "on standby" in case conditions change.
authors.affiliation: Environmental Genomics and Systems Biology, Lawrence Berkeley National Lab, Berkeley, California, United States of America.
authors.forename: Morgan N
authors.identifier: http://orcid.org/0000-0002-4251-0362
authors.initials: MN
authors.lastname: Price
authors.affiliation: Environmental Genomics and Systems Biology, Lawrence Berkeley National Lab, Berkeley, California, United States of America.
authors.forename: Kelly M
authors.initials: KM
authors.lastname: Wetmore
authors.affiliation: Environmental Genomics and Systems Biology, Lawrence Berkeley National Lab, Berkeley, California, United States of America.
authors.forename: Adam M
authors.initials: AM
authors.lastname: Deutschbauer
authors.affiliation: Environmental Genomics and Systems Biology, Lawrence Berkeley National Lab, Berkeley, California, United States of America.
authors.forename: Adam P
authors.initials: AP
authors.lastname: Arkin
mesh_terms: D004275:DNA, Ribosomal / Q000378:metabolism; D048168:Escherichia coli K12 / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism; D020869:Gene Expression Profiling; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D005947:Glucose / Q000378:metabolism; D010641:Phenotype; D040901:Proteomics
chemical_list: D004275:DNA, Ribosomal; D029968:Escherichia coli Proteins; D005947:Glucose