The Constructed Of DR₂566Mutant And Preliminary Functional Analysis Of DR₂566Gene In Deinococcus Radiodurans

Objective：To understand the function of DR₂566gene in the extreme resistance of DR, weused bioinformatic methods to analyze the DR₂566gene and constructed a DR₂566gene delete mutant strain of DR by homologous recombination. The function ofDR₂566in the super-resistance ability of DR was determined by exposing themutant strain and wild type strain by UV-radiation, H2O2and mitomycin respectively.Methods:1. Using bioinformatic methods to analyze advanced structure, physiochemicalproperties and biochemical function of DR₂566gene and its expression product.2．Using in vitro and in vivo homologous recombination method to constructDR₂566gene deletion mutant strain.3．Comparing the survival ratio of DR wild-type and DR₂566gene deletion mutantstrainafter UV irradiation, H2O2and mitomycin treatment, thereby, determing roughlythe contribution of DR₂566gene for the extreme resistance of DR.Results:1. The bioinformatic analysis results showed that based on the overall nucleotidesequence blast, homologous genes of DR₂566in other genomes was not found,which showed DR₂566is a specific geneof DR. Domain analysis suggests thatDR₂566is a member of the family of restriction endonuclease（restriction_endonuclease_like superfamily）, the short repair VSR nucleic acidenzyme functions （replication, recombination and repair）.2. Successfully amplified three fragments of DR₂566gene upstream, downstreamand contain the GroEL gene promoter Kan resistance gene by PCR, transformedconnection product of three fragments into into DR competent cell, screened positiveclones by kanamycin, and finally constructed the DR₂566gene deletion mutantstrain.3. Treating the mutant strain and wild type DR strain by UV-irradiaton, H2O2and mitomycin, and comparing the survival rate of these two DR strains. Results showedthat survival rate of DR₂566gene deletion mutant strain was obviously lower thanthat of wild type strain, and the difference was statistically significant （P <0.05）.Conclusions:Deletion of DR₂566gene caused the mutant strain sensitive to ultravioletradiation and hydrogen peroxide, and DNA repairing capacity also weakened. Resultssuggested that DR₂566gene plays a certain function in the super-resistance of DR.