Rajdeep Banerjee

I am working as a Scientist I at the Department of Biomolecular Chemistry, University of Wisconsin -Madison, Madison, USA. My work focuses on role of Fe and Fe-S cluster proteins in gene regulation of uropathogenic Escherichia coli (UPEC). I’ve dissected out the role of Fe-containing transcription factor Ferric Uptake Regulator (Fur) in UPEC. I found out that deletion of Fur leads to amino acid depletion leading to activation of stress response pathway through NtrC, ppGpp and RpoS. The increased amino acid demand of the fur mutant or iron chelated cells was exacerbated by aerobic conditions, which could be partly explained by the O2-dependent synthesis of the siderophore aerobactin, encoded by an operon within a pathogenicity island. Our data suggest that in the iron-poor environment of the urinary tract, amino acid availability could play a role in the proliferation of this uropathogen, particularly if there is sufficient O2 to produce aerobactin. This work was published in mBio in 2020. As a Ph. D student at University of Calcutta, India, I developed recombinant tools to study gene regulation of pathogenic Mycobacterium tuberculosis in non-pathogenic Escherichia coli. Using these tools, I was able to purify transcriptionally active recombinant Mycobacteria tuberculosis RNA polymerase and sigma factors in E. coli without the hazards of working with the pathogen (published in Tuberculosis). Moreover, I developed an mCherry based reporter assay to study gene regulation of Mycobacterium tuberculosis in vivo in E. coli (published in Journal of Bacteriology). These methods were used to decipher a novel mode of gene regulation by transcription factor Rv1222 (published in Nucleic Acid Research), and to study the role of polyphosphate kinase 1 (PPK1) in phosphate starvation stress response of Mycobacterium tuberculosis (published in Microbiology).