Characterization of a conserved interaction between DNA glycosylase and ParA in Mycobacterium smegmatis and M. tuberculosis.
The chromosome partitioning proteins, ParAB, ensure accurate segregation of genetic materials into daughter cells and most bacterial species contain their homologs. However, little is known about the regulation of ParAB proteins. In this study, we found that 3-methyladenine DNA glycosylase I MsTAG(Ms5082) regulates bacterial growth and cell morphology by directly interacting with MsParA (Ms6939) and inhibiting its ATPase activity in Mycobacterium smegmatis. Using bacterial two-hybrid and pull-down techniques in combination with co-immunoprecipitation assays, we show that MsTAG physically interacts with MsParA both in vitro and in vivo. Expression of MsTAG under conditions of DNA damage induction exhibited similar inhibition of growth as the deletion of the parA gene in M. smegmatis. Further, the effect of MsTAG on mycobacterial growth was found to be independent of its DNA glycosylase activity, and to result instead from direct inhibition of the ATPase activity of MsParA. Co-expression of these two proteins could counteract the growth defect phenotypes observed in strains overexpressing MsTAG alone in response to DNA damage induction. Based on protein co-expression and fluorescent co-localization assays, MsParA and MsTAG were further found to co-localize in mycobacterial cells. In addition, the interaction between the DNA glycosylase and ParA, and the regulation of ParA by the glycosylase were conserved in M. tuberculosis and M. smegmatis. Our findings provide important new insights into the regulatory mechanism of cell growth and division in mycobacteria.
National Key Laboratory of Agricultural Microbiology, Center for Proteomics Research, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China.
Feng
F
Huang
Zheng-Guo
ZG
He
D000251:Adenosine Triphosphatases / Q000037:antagonists & inhibitors / Q000378:metabolism; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000378:metabolism*; D015139:Blotting, Southern; D004249:DNA Damage; D045647:DNA Glycosylases / Q000737:chemistry / Q000378:metabolism*; D055786:Gene Knockout Techniques; D008969:Molecular Sequence Data; D020102:Mycobacterium smegmatis / Q000166:cytology / Q000201:enzymology* / Q000254:growth & development / Q000648:ultrastructure; D009169:Mycobacterium tuberculosis / Q000166:cytology / Q000201:enzymology* / Q000254:growth & development / Q000648:ultrastructure; D011485:Protein Binding; D021381:Protein Transport; D013045:Species Specificity; D013312:Stress, Physiological
D001426:Bacterial Proteins; C021565:3-methyladenine-DNA glycosylase; D045647:DNA Glycosylases; D000251:Adenosine Triphosphatases