%0 Journal Article %A Kurthkoti, Krishna %A Srinath, Thiruneelakantan %A Kumar, Pradeep %A Malshetty, Vidyasagar S. %A Sang, Pau Biak %A Jain, Ruchi %A Manjunath, Ramanathapuram %A Varshney, Umesh %T A distinct physiological role of MutY in mutation prevention in mycobacteria %D 2010 %J Microbiology, %V 156 %N 1 %P 88-93 %@ 1465-2080 %R https://doi.org/10.1099/mic.0.033621-0 %K GO or 8-oxoG, 7,8-dihydro-8-oxoguanine %K EMSA, electrophoretic mobility shift assay %K RRDR, rifampicin resistance determining region %I Microbiology Society, %X Oxidative damage to DNA results in the occurrence of 7,8-dihydro-8-oxoguanine (8-oxoG) in the genome. In eubacteria, repair of such damage is initiated by two major base-excision repair enzymes, MutM and MutY. We generated a MutY-deficient strain of Mycobacterium smegmatis to investigate the role of this enzyme in DNA repair. The MutY deficiency in M. smegmatis did not result in either a noteworthy susceptibility to oxidative stress or an increase in the mutation rate. However, rifampicin-resistant isolates of the MutY-deficient strain showed distinct mutations in the rifampicin-resistance-determining region of rpoB. Besides the expected C to A (or G to T) mutations, an increase in A to C (or T to G) mutations was also observed. Biochemical characterization of mycobacterial MutY (M. smegmatis and M. tuberculosis) revealed an expected excision of A opposite 8-oxoG in DNA. Additionally, excision of G and T opposite 8-oxoG was detected. MutY formed complexes with DNA containing 8-oxoG : A, 8-oxoG : G or 8-oxoG : T but not 8-oxoG : C pairs. Primer extension reactions in cell-free extracts of M. smegmatis suggested error-prone incorporation of nucleotides into the DNA. Based on these observations, we discuss the physiological role of MutY in specific mutation prevention in mycobacteria. %U https://www.microbiologyresearch.org/content/journal/micro/10.1099/mic.0.033621-0