GATC sequences, DNA nicks and the MutH function in Escherichia coli mismatch repair.
AUTOR(ES)
Längle-Rouault, F
RESUMO
Circular heteroduplex DNAs of bacteriophage phi X174 have been constructed carrying either a G:T (Eam+/Eam3) or a G:A (Bam+/Bam16) mismatch and containing either two, one or no GATC sequences. Mismatches were efficiently repaired in wild-type Escherichia coli transfected with phi X174 heteroduplexes only when two unmethylated GATC sequences were present in phi X174 DNA. The requirements for GATC sequences in substrate DNA and for the E. coli MutH function in E. coli mismatch repair can be alleviated by the presence of a persistent nick (transfection with nicked heteroduplex DNA in ligase temperature-sensitive mutant at 40 degrees C). A persistent nick in the GATC sequence is as effective in stimulating mutL- and mutS-dependent mismatch repair as a nick distant from the GATC sequence and from the mismatch. These observations suggest that the MutH protein participates in methyl-directed mismatch repair by recognizing unmethylated DNA GATC sequences and/or stimulating the nicking of unmethylated strands.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=553511Documentos Relacionados
- Mutation spectrum in Escherichia coli DNA mismatch repair deficient (mutH) strain.
- Depletion of the cellular amounts of the MutS and MutH methyl-directed mismatch repair proteins in stationary-phase Escherichia coli K-12 cells.
- Mutation detection with MutH, MutL, and MutS mismatch repair proteins.
- Influence of GATC sequences on Escherichia coli DNA mismatch repair in vitro.
- Requirement for d(GATC) sequences in Escherichia coli mutHLS mismatch correction.