Selection for Chromosome Architecture in Bacteria
- 445 Downloads
Bacterial chromosomes are immense polymers whose faithful replication and segregation are crucial to cell survival. The ability of proteins such as FtsK to move unidirectionally toward the replication terminus, and direct DNA translocation into the appropriate daughter cell during cell division, requires that bacterial genomes maintain an architecture for the orderly replication and segregation of chromosomes. We suggest that proteins that locate the replication terminus exploit strand-biased sequences that are overrepresented on one DNA strand, and that selection increases with decreased distance to the replication terminus. We report a generalized method for detecting these architecture imparting sequences (AIMS) and have identified AIMS in nearly all bacterial genomes. Their increased abundance on leading strands and decreased abundance on lagging strands toward replication termini are not the result of changes in mutational bias; rather, they reflect a gradient of long-term positive selection for AIMS. The maintenance of the pattern of AIMS across the genomes of related bacteria independent of their positions within individual genes suggests a well-conserved role in genome biology. The stable gradient of AIMS abundance from replication origin to terminus suggests that the replicore acts as a target of selection, where selection for chromosome architecture results in the maintenance of gene order and in the lack of high-frequency DNA inversion within replicores.
KeywordsGenome evolution FtsK Replication terminus DNA strand bias Mutational bias Natural selection
This work was supported by Grant MCB-0217278 from the National Science Foundation to J.G.L. and a fellowship from the Pennsylvania Space Consortium to H.H. We thank Thomas Murphy VII for assistance with automated global pairwise sequence comparisons.
- Andersson JO, Andersson SG (1999a) Genome degradation is an ongoing process in Rickettsia. Mol Biol Evol 16:1178–1191Google Scholar
- Cole ST, Eiglmeier K, Parkhill J, James KD, Thomson NR, Wheeler PR, Honore N, Garnier T, Churcher C, Harris D, Mungall K, Basham D, Brown D, Chillingworth T, Connor R, Davies RM, Devlin K, Duthoy S, Feltwell T, Fraser A, Hamlin N, Holroyd S, Hornsby T, Jagels K, Lacroix C, Maclean J, Moule S, Murphy L, Oliver K, Quail MA, Rajandream MA, Rutherford KM, Rutter S, Seeger K, Simon S, Simmonds M, Skelton J, Squares R, Squares S, Stevens K, Taylor K, Whitehead S, Woodward JR, Barrell BG (2001) Massive gene decay in the leprosy bacillus. Nature 409:1007–1011CrossRefPubMedGoogle Scholar
- Foster J, Ganatra M, Kamal I, Ware J, Makarova K, Ivanova N, Bhattacharyya A, Kapatral V, Kumar S, Posfai J, Vincze T, Ingram J, Moran L, Lapidus A, Omelchenko M, Kyrpides N, Ghedin E, Wang S, Goltsman E, Joukov V, Ostrovskaya O, Tsukerman K, Mazur M, Comb D, Koonin E, Slatko B (2005) The Wolbachia genome of Brugia malayi: endosymbiont evolution within a human pathogenic nematode. PLoS Biol 3:e121CrossRefPubMedGoogle Scholar
- Lawrence JG, Hendrickson H (2004) Chromosome structure and constraints on lateral gene transfer. Dev Genet 2004:319–336Google Scholar
- Lawrence JG, Roth JR (1999) Genomic flux: genome evolution by gene loss and acquisition. In: Charlebois RL (eds). Organization of the prokaryotic genome. ASM Press, Washington, DC, pp 263–289Google Scholar
- Liu SL, Sanderson KE (1995a) The chromosome of Salmonella paratyphi A is inverted by recombination between rrnH and rrnG. J Bacteriol 177:6585–6592Google Scholar
- Liu SL, Sanderson KE (1995b) Rearrangements in the genome of the bacterium Salmonella typhi. Proc Natl Acad Sci USA 92:1018–1022Google Scholar
- Parkhill J, Sebaihia M, Preston A, Murphy LD, Thomson N, Harris DE, Holden MT, Churcher CM, Bentley SD, Mungall KL, Cerdeno-Tarraga AM, Temple L, James K, Harris B, Quail MA, Achtman M, Atkin R, Baker S, Basham D, Bason N, Cherevach I, Chillingworth T, Collins M, Cronin A, Davis P, Doggett J, Feltwell T, Goble A, Hamlin N, Hauser H, Holroyd S, Jagels K, Leather S, Moule S, Norberczak H, O’Neil S, Ormond D, Price C, Rabbinowitsch E, Rutter S, Sanders M, Saunders D, Seeger K, Sharp S, Simmonds M, Skelton J, Squares R, Squares S, Stevens K, Unwin L, Whitehead S, Barrell BG, Maskell DJ (2003) Comparative analysis of the genome sequences of Bordetella pertussis, Bordetella parapertussis and Bordetella bronchiseptica. Nat Genet 35:32–40CrossRefPubMedGoogle Scholar
- Read TD, Brunham RC, Shen C, Gill SR, Heidelberg JF, White O, Hickey EK, Peterson J, Utterback T, Berry K, Bass S, Linher K, Weidman J, Khouri H, Craven B, Bowman C, Dodson R, Gwinn M, Nelson W, DeBoy R, Kolonay J, McClarty G, Salzberg SL, Eisen J, Fraser CM (2000) Genome sequences of Chlamydia trachomatis MoPn and Chlamydia pneumoniae AR39. Nucleic Acids Res 28:1397–1406CrossRefPubMedGoogle Scholar