The Life-cycle of Operons

Journal Article · Thu Mar 15 04:00:00 EDT 2007 · PLoS Genetics

OSTI ID:922706

Price, Morgan N; Arkin, Adam P; Alm, Eric J

Operons are a major feature of all prokaryotic genomes, buthow and why operon structures vary is not well understood. To elucidatethe life-cycle of operons, we compared gene order between Escherichiacoli K12 and its relatives and identified the recently formed anddestroyed operons in E. coli. This allowed us to determine how operonsform, how they become closely spaced, and how they die. Our findingssuggest that operon evolution may be driven by selection on geneexpression patterns. First, both operon creation and operon destructionlead to large changes in gene expression patterns. For example, theremoval of lysA and ruvA from ancestral operons that contained essentialgenes allowed their expression to respond to lysine levels and DNAdamage, respectively. Second, some operons have undergone acceleratedevolution, with multiple new genes being added during a brief period.Third, although genes within operons are usually closely spaced becauseof a neutral bias toward deletion and because of selection against largeoverlaps, genes in highly expressed operons tend to be widely spacedbecause of regulatory fine-tuning by intervening sequences. Althoughoperon evolution may be adaptive, it need not be optimal: new operonsoften comprise functionally unrelated genes that were already inproximity before the operon formed.

• Research Organization: Ernest Orlando Lawrence Berkeley NationalLaboratory, Berkeley, CA (US)
• Sponsoring Organization: USDOE Director. Office of Science. Biological andEnvironmental Research
• DOE Contract Number: AC02-05CH11231
• OSTI ID: 922706
• Report Number(s): LBNL--60281; BnR: KP1102010
• Journal Information: PLoS Genetics, Journal Name: PLoS Genetics Journal Issue: 6 Vol. 2
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
DNA DAMAGES
ESCHERICHIA COLI
Evolutionary Biology
GENES
LIFE CYCLE
LYSINE
REMOVAL