University of Wisconsin–Madison
College of Agriculture and Life Sciences | School of Medicine and Public Health

Richard Gourse

Professor

rgourse@bact.wisc.edu

608-262-9813

Bacteriology
Control of gene expression and the structure of the bacterial chromosome

Address
5470 Microbial Sciences Building
Lab Website
http://www.bact.wisc.edu/faculty.php?init=RLG&show=PEP
Department
Bacteriology
Research Interests
We study the control of gene expression and the structure of the bacterial choromosome.
Research Fields
Gene Expression

Research Description:
We study fundamental issues in the molecular biology of gene expression in bacteria using biochemical, genetic, structural, and microscopy approaches. At present, we are focused primarily on the mechanism of transcription initiation, the architecture of transcription complexes, the relationship between structure and function of RNA polymerase (RNAP), and the mechanisms by which the transcription apparatus responds to signals from inside and outside of the cell. We have studied the control of ribosome synthesis in Escherichia coli, because this is so central to cell function, because rRNA promoters account for the majority of transcription in the cell, and because the genes for rRNA and other parts of the translation machinery display a fascinating and complex network of regulatory responses. In recent years we have discovered that the factors responsible for controlling rRNA synthesis also regulate hundreds of other genes, and we have begun to study the regulation of many of those genes as well. Current projects in the lab include studies on (i) the conformational changes in the promoter-RNAP complex that account for the tremendous variation in activity that occurs in response to differences in natural promoter sequences, (ii) the transcription factors ppGpp and DksA and their interactions with RNAP responsible for transcription regulation, and (iii) a transcription factor that facilitates RNA polymerase assembly. In addition, using tools of cell biology including fluorescence microscopy, we have discovered that bacteria contain nucleolus-like structures; i.e. rRNA operons come together in space even though the rRNA genes are spread out over 180 degrees of the circular E. coli chromosome. We are now exploring the factors that are responsible for these long-range interactions and their contributions to chromosome folding.


Representative Publications:
Search PubMed for more publications by Richard Gourse

Ross W, Vrentas CE, Sanchez-Vazquez P, Gaal T, Gourse RL. 2013. The Magic Spot: A ppGpp Binding Site on E. coli RNA Polymerase Responsible for Regulation of Transcription Initiation. Mol Cell 50:420-429. PMID:23623682

Winkelman JT, Winkelman BT, Boyce J, Maloney MF, Chen AY, Ross W, Gourse RL. 2015. Crosslink Mapping at Amino Acid-Base Resolution Reveals the Path of Scrunched DNA in Initial Transcribing Complexes. Mol Cell 59:768-780. PMID: 26257284

Winkelman JT*, Chandrangsu P*, Ross W, Gourse RL. 2016. Open complex scrunching before nucleotide addition accounts for the unusual transcription start site of E. coli ribosomal RNA promoters. Proc Natl Acad Sci USA 113: E1787-E1795. PMID:26976590 (*co-first authors)

Ross W, Sanchez-Vazquez P, Chen AC, Lee J-H, Burgos HL, Gourse RL. 2016. ppGpp binding to a site at the RNAP-DksA interface accounts for its dramatic effects on transcription initiation during the stringent response. Mol Cell 62:811-23. PMID:27237053

Gaal T, Bratton BP, Sanchez-Vazquez P, Sliwicki A, Sliwicki K, Vegel A, Pannu R, Gourse RL. 2016. Co-localization of distant chromosomal loci in space in E. coli: a bacterial nucleolus. Genes Dev 30:2272-2285. PMID:27898392

Gopalkrishnan S, Ross W, Chen AY, Gourse RL. 2017. TraR directly regulates transcription initiation by mimicking the combined effects of the global regulators DksA and ppGpp. Proc Natl Acad Sci USA 114(28):E5539-E5548. PMID:28652326