Regulatory Mechanisms in Bacterial Pathogens
This work is focused on understanding mechanisms utilized for bacterial colonization, and in particular in the ability of in vivo environmental factors to modulate bacterial gene expression. Transcriptional regulatory mechanisms have been defined on a global level in the pathogenic Neisseria species. We have established that the expression of virulence factors in these organisms is controlled by a global regulatory protein (ferric uptake regulator protein, Fur). We have established that the transcriptional regulatory protein Fur controls the expression of numerous genes that are required for the virulence of N. meningitidis and N. gonorrhoeae and have established that many of these genes are expressed in vivo during mucosal gonococcal infection in both men and women. Current studies are aimed at examining the regulation and expression of Fur-regulated genes in vitro, and in vivo directly in clinical specimens. We have also recently identified a novel mechanism for Fur-mediated regulation through small regulatory RNAs (sRNA) in both N. meningitidis and N. gonorrhoeae. We have established that in N. meningitidis the sRNA, NrrF functions independently of the cofactor RNA-binding protein, Hfq. Current studies are focused on defining how NrrF functions independently of Hfq and on identifying additional sRNAs using high-density oligonucleotide microarrays together with computational analysis.
Figure right: Native-PAGE visualized with a Typhoon 9400 fluorescence scanner: detection of Nrrf and SDHC without HFQ or with increasing concentrations of HFQ.
Figure left: Iron regulated transcription from intergenic regions. Microarray from wt intergenic regions showing expression profiles +Fe or -Fe.