The Life-cycle of Operons

Journal Article · Fri Nov 18 04:00:00 EST 2005 · PLoS Genetics

OSTI ID:889264

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

Operons are a major feature of all prokaryotic genomes, but how and why operon structures vary is not well understood. To elucidate the life-cycle of operons, we compared gene order between Escherichia coli K12 and its relatives and identified the recently formed and destroyed operons in E. coli. This allowed us to determine how operons form, how they become closely spaced, and how they die. Our findings suggest that operon evolution is driven by selection on gene expression patterns. First, both operon creation and operon destruction lead to large changes in gene expression patterns. For example, the removal of lysA and ruvA from ancestral operons that contained essential genes allowed their expression to respond to lysine levels and DNA damage, respectively. Second, some operons have undergone accelerated evolution, with multiple new genes being added during a brief period. Third, although most operons are closely spaced because of a neutral bias towards deletion and because of selection against large overlaps, highly expressed operons tend to be widely spaced because of regulatory fine-tuning by intervening sequences. Although operon evolution seems to be adaptive, it need not be optimal: new operons often comprise functionally unrelated genes that were already in proximity before the operon formed.

• Research Organization: Ernest Orlando Lawrence Berkeley NationalLaboratory, Berkeley, CA (US)
• Sponsoring Organization: USDOE Director. Office of Science. Office of Biological andEnvironmental Research, Genomics:GTL Program; Howard Hughes MedicalInstitute
• DOE Contract Number: AC02-05CH11231
• OSTI ID: 889264
• Report Number(s): LBNL--61256; BnR: KP1102010
• Journal Information: PLoS Genetics, Journal Name: PLoS Genetics Journal Issue: 7 Vol. 2
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
59 BASIC BIOLOGICAL SCIENCES
DNA DAMAGES
ESCHERICHIA COLI
GENES
LIFE CYCLE
LYSINE
Operon genome life-cycle gene expression
REMOVAL