Areas of Interest
I. Technology
A strong barrage of single-molecule experimental work during the
past decade has greatly expanded our capability in dissecting
the real time dynamics of complicated molecular interactions. We
are developing imaging technologies to apply single-molecule
imaging to the studies of live cells. We do this for two
purposes. (1) To have nanoscopic observations of the molecular
localization or dynamics in cells. This can be done because
single-molecule imaging is not constrained by the so-called
“diffraction-limit” that makes normal fluorescence microscope
have only micrometer-level spatial resolutions. (2) To follow
real-time protein expression. We have developed assays to
monitor the intracellular synthesis of individual protein
molecules. This allows us to decipher the gene expression
process with very high spatial and temporal resolution.
II. Biology
Over the last decade, a common theme emerged from the studies of
bacteria of many different species is that there is a great
degree of order in the intracellular organizations, in contrast
to conventional wisdom. We are particularly interested in two
proteins FtsZ and MreB, which are prokaryotic analog of
eukaryotic cytoskeleton proteins: tubulin and actin. We are
trying to understand why do bacterial cells need these proteins,
despite their small sizes, and how does these prokaryotic
cytoskeletal protein interact with each other and other cellular
components to fulfill their functions.
Neronal synapse function and plasticity depend on the
physical structure of the dendritic spines which, in turn,
responds to the synaptic activities. Identifying the mechanisms
underlying this process is the key to understand neuron
functioning. We are analyzing two aspects of this complex
process: 1. the (re)organization of actin cytoskeleton in the
spines; 2. the regulation of protein synthesis at dendrites in
response to nearly synaptic activities.
Selected Publications
Lili Niu and Ji Yu. Investigating Intracellular Dynamics of FtsZ
Cytoskeleton with Photo-activation Single-molecule Tracking
Biophysical Journal (2008).
J. Yu*, J. Xiao*, X. Ren, KQ. Lao and X. Sunney Xie. Probing
gene expression in live single Escherichia coli cells - one
molecule at a time. Science 311, 1600-1603 (2006).
J. Yu, D. Hu and P. F. Barbara. Unmasking Electronic Energy
Transfer of Conjugated Polymers by Suppression of O2 Quenching.
Science 289, 1327 (2000).
D. Hu, J. Yu, K. Wong, B. Bagchi, P. J. Rossky and P. F.
Barbara. Collapse of stiff conjugated polymers with chemical
defects into ordered, cylindrical conformations". Nature 405,
1030-1033 (2000). |
