Linked Life Data

17675652

Source:http://linkedlifedata.com/resource/pubmed/id/17675652

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
10
pubmed:dateCreated
2007-10-9
pubmed:abstractText
Escherichia coli have evolved adaptive systems to resist strongly acidic habitats in part through the production of 2 biochemically identical isoforms of glutamate decarboxylase (GAD), encoded by the gadA and gadB genes. These genes occur in E. coli and other members of the genospecies (e.g., Shigella spp.) and originated as part of a genomic fitness island acquired early in Escherichia evolution. The present duplicated gad loci are widely spaced on the E. coli chromosome, and the 2 genes are 97% similar in sequence. Comparison of the nucleotide sequences of the gadA and gadB in 16 strains of pathogenic E. coli revealed 3.8% and 5.0% polymorphism in the 2 genes, respectively. Alignment of the homologous genes identified a total of 120 variable sites, including 21 fixed nucleotide differences between the loci within the first 82 codons of the genes. Twenty-three phylogenetically informative sites were polymorphic for the same nucleotides in both genes suggesting recent gene conversions or intergenic recombination. Phylogenetic analysis based on the synonymous substitutions per synonymous site indicated 2 cases in which specific gadA and gadB alleles were more closely related to one another than to other alleles at the corresponding locus. The results indicate that at least 3 gene conversion events have occurred after the gad gene duplication in the evolution of E. coli. Despite multiple gene conversion events, the upstream regulatory regions and the 5' end of each gene remains distinct, suggesting that maintaining functionally different gad genes is important in this acid-resistance mechanism in pathogenic E. coli.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
0737-4038
pubmed:author
pubmed:issnType
Print
pubmed:volume
24
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
2323-33
pubmed:dateRevised
2008-11-21
pubmed:meshHeading
pubmed:year
2007
pubmed:articleTitle
Recent gene conversions between duplicated glutamate decarboxylase genes (gadA and gadB) in pathogenic Escherichia coli.
pubmed:affiliation
Microbial Evolution Laboratory, National Food Safety & Toxicology Center, Michigan State University, East Lansing, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, Non-P.H.S., Research Support, Non-U.S. Gov't, Research Support, N.I.H., Extramural