Sequence and stress-response analyses of the DNA mismatch repair gene hexA in Lactococcus lactis.
The DNA mismatch repair gene hexA was identified in Lactococcus lactis by PCR amplification by using a pair of primers homologous to the DNA-binding Dps protein. The gene in its entirety, including the regulatory regions, was sequenced, by using a strategy of chromosomal walking based on two PCR protocols. The open reading frame of 2526 bp was preceded by a strong ribosome-binding site (AGGAAG) and was followed by a potential transcription terminator (hairpin loop structure). The 5' terminus of the hexA mRNA was located 135 bp upstream of the start codon, and putative -10 and -35 regions were identified. The deduced amino acid sequence revealed two motifs, the ATP/GTP-binding site (P-loop) and the "MutS family signature". The hexA promoter was cloned into pMU1327, which contained a promoter-less CAT reporter gene, and the promoter activity was examined under oxidative-stress conditions. It appears that the promoter activity is down-shifted by H2O2 at 4 mM.
Ren
J
J
Department of Biotechnology, University of New South Wales, Sydney, Australia.
Park
J H
JH
Dunn
N W
NW
Kim
W S
WS
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D020137:Base Pair Mismatch; D004260:DNA Repair; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial; D018869:Heat-Shock Response; D006861:Hydrogen Peroxide / Q000494:pharmacology; D013294:Lactococcus lactis / Q000235:genetics* / Q000254:growth & development / Q000502:physiology*; D008969:Molecular Sequence Data; D018384:Oxidative Stress; D011401:Promoter Regions, Genetic / Q000235:genetics; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA
D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; C084499:HexA protein, bacteria; D006861:Hydrogen Peroxide