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Novel ionizing radiation-sensitive mutants of Deinococcus radiodurans
K S Udupa1, P A O'Cain, V Mattimore
1Department of Microbiology, Louisiana State University, Baton Rouge 70803.
Journal of Bacteriology
|December 1, 1994
Summary
Two new genes, irrB and irrI, were found in Deinococcus radiodurans, impacting resistance to radiation. Their interaction with the uvrA gene influences sensitivity to ionizing and UV radiation.
Area of Science:
- Microbiology
- Radiation Biology
- Genetics
Background:
- Deinococcus radiodurans exhibits remarkable resistance to ionizing radiation.
- Understanding the genetic basis of radiation resistance is crucial for various applications.
Purpose of the Study:
- To identify and characterize novel genetic loci involved in radiation resistance in D. radiodurans.
- To investigate the interplay between newly identified loci and known DNA repair genes like uvrA.
Main Methods:
- Genetic analysis involving gene inactivation and creation of double mutants.
- Phenotypic characterization of radiation resistance (ionizing and UV) in wild-type and mutant strains.
- Gene mapping to determine the physical location of the identified loci.
Main Results:
- Identification of two new radiation resistance loci, irrB and irrI.
- Inactivation of irrB or irrI confers partial resistance loss to ionizing radiation.
- Differential effects of uvrA inactivation on irrB and irrI mutant phenotypes.
- Both mutations reduce UV radiation resistance, especially in a uvrA+ background.
- The irrB and irrI genes are located approximately 20 kb apart, flanking the uvrA and pol genes.
Conclusions:
- The irrB and irrI loci play significant roles in D. radiodurans's resistance to ionizing and UV radiation.
- The functional relationship between irrB, irrI, and uvrA is complex and locus-specific.
- These findings expand our understanding of the intricate DNA repair pathways in D. radiodurans.