GC-rich intra-operonic spacers in prokaryotes: possible relation to gene order conservation.
Genome-scale compositional analyses of non-coding sequences from 410 microbes of varying GC-content, lineage, environment/life-style, reveal presence of a distinct trend in GC-usage in spacers between intra-operonic and extra-operonic gene-pairs. For most of the microbes, average GC-content of the intra-operonic spacers are consistently higher than those between extra-operonic unidirectional gene-pairs. Also, unidirectional gene-pairs exhibiting higher cross-species conservation, irrespective of their operonic context, house relatively GC-rich spacers. A few prokaryotes, most of which represent known cases of genome degradation, stand out as exceptions defying this trend. GC-enrichment of intra-operonic spacers therefore appears to be an evolutionary strategy facilitating preservation of operonic gene-order.
Structural Biology & Bioinformatics Division, Indian Institute of Chemical Biology, 4, Raja S. C. Mullick Road, Kolkata 700 032, India. webanirban@gmail.com
Anirban
A
Dutta
Sandip
S
Paul
Chitra
C
Dutta
D001105:Archaea / Q000235:genetics*; D001419:Bacteria / Q000235:genetics*; D001482:Base Composition; D017124:Conserved Sequence; D020862:GC Rich Sequence; D023061:Gene Order; D023281:Genomics / Q000379:methods*; D009876:Operon / Q000235:genetics*