Disease relevance of recD

• The recombination hot spot chi activates RecBCD recombination by converting Escherichia coli to a recD mutant phenocopy [1].
• Salmonella recD mutations increase recombination in a short sequence transduction assay [2].
• We have identified recD mutants of Salmonella typhimurium by their ability to support growth of phage P22 abc (anti-RecBCD) mutants, whose growth is prevented by normal host RecBCD function [2].
• The effect of a recipient recD mutation was eliminated if the donor P22 phage expressed its Abc (anti-RecBC) function [2].
• Exonuclease requirements for recombination of lambda-phage in recD mutants of Escherichia coli [3].

High impact information on recD

• Chi is dispensable when cells are induced for the SOS response or contain a recD mutation. recBC sbcA mutant cells are also capable of RDR induction [4].
• Upon delivering a double-chain break to the plasmid, lambda recombined as if the cells had become recD mutants [1].
• Two other suppressors, hopR and hopE of the same -1 frameshift mutant, cause some ribosomes reading the sequence GUG UG to decode a single amino acid, Val, from the five nucleotides [5].
• The recB and recD subunits of the recBCD enzyme (exonuclease V) from Escherichia coli were covalently photolabeled with the ATP photoaffinity analogue [alpha-32P]8-azido-ATP [6].
• Complete nucleotide sequence of recD, the structural gene for the alpha subunit of Exonuclease V of Escherichia coli [7].

Biological context of recD

• The proposed initiation codon of the recD gene overlaps the termination codon of the upstream recB gene by one nucleotide, suggesting that these genes may form an operon [7].
• Introducing a deletion into the nonoverlapping portion of the cloned thyA gene and inserting a gene encoding kanamycin resistance produced a (delta thyA::Kmr) that was easily transferred to the chromosome of a recD host by marker replacement [8].
• Trans-complementation and freshly targeted gene disruption studies reconfirmed that the inactivation of the recD gene leads to a cold-sensitive phenotype [9].
• The inactivation of recD in P. syringae also led to cell death and accumulation of DNA fragments of approximately 25-30 kbp in size at low temperature (4 degrees ) [9].
• Transposon mutagenesis was carried out to isolate mutant(s) of the bacterium that are defective for growth at 4 degrees but normal at 22 degrees . In one such cold-sensitive mutant (CS1), the transposon-disrupted gene was identified to be a homolog of the recD gene of several bacteria [9].

Associations of recD with chemical compounds

• A knockout of gshA, involved in glutathione biosynthesis, enhanced the susceptibility to metronidazole, while a knockout of recD, involved in recombination and repair, made the bacteria hypersusceptible to ciprofloxacin [10].

Other interactions of recD

• Mutation of recN reduced sectored recombinants in these crosses to approximately 1% in all the strains examined, including recD [11].
• In wild-type cells, induction of recA expression by naladixic acid required the recBC, but not the recD function of the RecBCD enzyme [12].

References