Jie Xiao
Johns Hopkins University, MD·Biophysics
Bacteria must divide cleanly and keep their DNA neatly organized and active, all inside a tiny, crowded cell. The lab asks how these essential processes are arranged in space and time in living bacteria.
- Fields
Biophysics
Microbiology & Immunology
Biochemistry
- Topics
DNA supercoiling
transcription regulation
RNA polymerase
- Grants
- 2 known grants, through Mar 2030
What they work on
- Measure how DNA supercoiling changes transcription speed and coupling between neighboring RNA polymerase molecules, using single-molecule imaging of purified RNA polymerase and DNA constructs.
- Determine how chromosomal topological domains affect gene expression in live bacteria, using single-molecule FISH to count RNAs and single-molecule gene expression reporters.
- Build coarse-grained models of DNA base-pairing under torque, informed by the experiments, to create a quantitative framework for how supercoiling regulates transcription across molecular and time scales.
- Identify the components of the core septal cell wall synthase complex in E. coli, and how two complementary synthase systems achieve continuous wall synthesis, using live-cell single-molecule tracking and biochemical analyses.
- Map the location and movement of cell wall hydrolases at the division site, and test how the DNA-binding protein HU, small noncoding RNAs and supercoiling compact the E. coli chromosome.
More about the research
Its central tool is single-molecule imaging, which lets researchers track individual protein molecules moving in live cells and link that movement to what the proteins do. A recurring theme is DNA supercoiling, the over- or under-twisting of the DNA double helix. This twisting may help pack the chromosome and may also control which genes are turned on.
Why it matters
Bacterial cell division and genome organization are essential for bacterial survival. Knowing how the molecules behind them are coordinated could reveal weak points relevant to therapeutics, and the projects point to this possibility. A new picture of how DNA twisting controls genes could also change how scientists understand gene regulation beyond transcription factors.
Known grants
From NIH and NSF research grants. Labs often have other funding we can't see.
Closest labs
Rasika Harshey
University of Texas at Austin, TX·Microbiology & Immunology
Use phage Mu transposition, which inserts DNA almost anywhere, to build a high-resolution map of contacts between genomic loci in E. coli and test how genome organization influences gene expression.
Richard Ebright
Rutgers University-New Brunswick, NJ·Biochemistry
Determine structures of intact, functional factor-dependent pre-termination complexes from E. coli and the archaeon Thermococcus kodakarensis by cryo-electron microscopy, defining how the ATP-driven RNA motor Rho and the RNA-cutting enzyme aCPSF1 engage RNA polymerase.
Peng Chen
Cornell University, NY·Chemistry
Define how the electron-relay protein CymA changes its location and movement in live Shewanella oneidensis cells as electron transfer activity rises, using single-molecule fluorescence imaging and single-cell electrochemical control.
The school
Johns Hopkins University: 100 labs on PI Pages, $4.1B a year on research, 622 research doctorates a year.
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