Document Detail

Mutations in polI but not mutSLH destabilize Haemophilus influenzae tetranucleotide repeats.
MedLine Citation:
PMID:  11889052     Owner:  NLM     Status:  MEDLINE    
Haemophilus influenzae (Hi), an obligate upper respiratory tract commensal/pathogen, uses phase variation (PV) to adapt to host environment changes. Switching occurs by slippage of nucleotide repeats (microsatellites) within genes coding for virulence molecules. Most such microsatellites in Hi are tetranucleotide repeats, but an exception is the dinucleotide repeats in the pilin locus. To investigate the effects on PV rates of mutations in genes for mismatch repair (MMR), insertion/deletion mutations of mutS, mutL, mutH, dam, polI, uvrD, mfd and recA were constructed in Hi strain Rd. Only inactivation of polI destabilized tetranucleotide (5'AGTC) repeat tracts of chromosomally located reporter constructs, whereas inactivation of mutS, but not polI, destabilized dinucleotide (5'AT) repeats. Deletions of repeats were predominant in polI mutants, which we propose are due to end-joining occurring without DNA polymerization during polI-deficient Okazaki fragment processing. The high prevalence of tetranucleotides mediating PV is an exceptional feature of the Hi genome. The refractoriness to MMR of hypermutation in Hi tetranucleotides facilitates adaptive switching without the deleterious increase in global mutation rates that accompanies a mutator genotype.
Christopher D Bayliss; Tamsin van de Ven; E Richard Moxon
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  The EMBO journal     Volume:  21     ISSN:  0261-4189     ISO Abbreviation:  EMBO J.     Publication Date:  2002 Mar 
Date Detail:
Created Date:  2002-03-12     Completed Date:  2002-04-29     Revised Date:  2009-11-18    
Medline Journal Info:
Nlm Unique ID:  8208664     Medline TA:  EMBO J     Country:  England    
Other Details:
Languages:  eng     Pagination:  1465-76     Citation Subset:  IM    
Molecular Infectious Diseases Group, Department of Paediatrics, Weatherall Institute for Molecular Medicine, John Radcliffe Hospital, Headington, Oxford OX3 9DU, UK.
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MeSH Terms
Adenosine Triphosphatases*
Bacterial Proteins / genetics,  physiology*
Base Pair Mismatch*
DNA Polymerase I / genetics,  physiology*
DNA Repair*
DNA Repair Enzymes*
DNA, Bacterial*
DNA-Binding Proteins / genetics,  physiology*
Dinucleotide Repeats
Endodeoxyribonucleases / genetics,  physiology*
Epitopes, B-Lymphocyte / immunology
Escherichia coli Proteins*
Haemophilus influenzae / enzymology*,  genetics
Lipopolysaccharides / immunology
Microsatellite Repeats*
MutS DNA Mismatch-Binding Protein
Reg. No./Substance:
0/Bacterial Proteins; 0/DNA, Bacterial; 0/DNA-Binding Proteins; 0/Epitopes, B-Lymphocyte; 0/Escherichia coli Proteins; 0/Lipopolysaccharides; 0/MutL protein, E coli; EC 2.7.7.-/DNA Polymerase I; EC 3.1.-/Endodeoxyribonucleases; EC 3.1.21.-/methyl-directed mismatch repair protein, E coli; EC 3.6.1.-/Adenosine Triphosphatases; EC DNA Mismatch-Binding Protein; EC protein, E coli; EC 6.5.1.-/DNA Repair Enzymes
Erratum In:
EMBO J 2002 Aug 15;21(16):4391

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