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== Announcements ==  
== Announcements ==  
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Lunch & Learn 10/25/2012
Lunch & Learn 11/08/2012


OPTICAL FORCE PROBE STUDIES OF THE PERICELLULAR COAT
TRANSCRIPTIONAL BURST GENERATION VIA CLUSTERING
Louis McLane (Curtis Lab)
James Waters (Kim Lab)


A voluminous polymer coat adorns the surface of many eukaryotic cells. Although the pericellular matrix (PCM) often extends several microns from the cell surface, its macromolecular structure remains elusive. This massive cellular organelle negotiates the cell’s interaction with surrounding tissue, influencing important processes including cell adhesion, mitosis, locomotion, molecular sequestration, and mechanotransduction. Investigations of the PCM’s architecture and function have been hampered by the difficulty of visualizing this invisible hydrated structure without disrupting its integrity. In this work, we establish several assays to non-invasively measure the ultrastructure of the PCM. Optical force probe assays show that the PCM of chondrocytes (RCJ-P) is not crosslinked and that it easily reconfigures around microparticles. We report distinct changes in forces measured from PCMs treated with exogenous aggrecan, illustrating the assay’s potential to probe proteoglycan distribution. Measurements detect an exponentially-increasing osmotic force in the PCM arising from an inherent concentration gradient. With this result, we estimate the variation of the PCM’s mesh size (correlation length) to range from approximately 100 nm at the surface to 500 nm at its periphery. Quantitative particle exclusion assays confirm this prediction, and show that the PCM acts like a sieve. These assays provide a much needed tool to study PCM ultrastructure and its poorly defined but important role in fundamental cellular processes.
Certain gene transcription events occur in interesting temporal patterns, inadequately described by first-order kinetics, while still being governed by inherently stochastic processes. For instance, the production of messenger RNA in yeast cells is characterized by large bursts as opposed to individual uncorrelated events. We are investigating the co-localization or clustering of active sites as a mechanism to control this effect and we attempt to reproduce these bursts through numerical simulation of transcription factors diffusing in a model yeast nucleus. We present a detailed introduction to the development of our computational model, as well as preliminary results describing the effect of clustering sites on transcriptional bursting.
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Revision as of 09:36, 5 November 2012

This is the homepage of the Georgia Tech node of the international Physics of Living Systems (PoLS) student research network. The goal of this network is to foster interaction and collaboration among PoLS researchers within Georgia Tech and across institutes. Six core faculty members from the Schools of Biology, Physics, and Mechanical Engineering lead the Georgia Tech PoLS node.

The NSF Physics of Living Systems program sponsors research "exploring the most fundamental physical processes that living systems utilize to perform their functions in dynamic and diverse environments." The aim of PoLS research is to advance our understanding of the living world in a quantitative way, while also seeking to expand the intellectual range of physics paying through the lessons learned from the biological study.

At Georgia Tech PoLS research is carried out across a diversity of biological scales: single-molecule ⇒ cellular ⇒ organismal biophysics. Both theoretical and experiment biophysics research is conducted by core faculty members and affiliated faculty.

Signing-up for the email list

To receive email notification about upcoming GaTech-PoLS events and reminders about the weekly talks, sign-up for the email list. You can sign-up by simply sending a message 

To: pols-request@lists.gatech.edu
Subject: subscribe

You should immediately receive a response telling you that you have joined.

Announcements

 
Lunch & Learn 11/08/2012

TRANSCRIPTIONAL BURST GENERATION VIA CLUSTERING
James Waters (Kim Lab)

Certain gene transcription events occur in interesting temporal patterns, inadequately described by first-order kinetics, while still being governed by inherently stochastic processes. For instance, the production of messenger RNA in yeast cells is characterized by large bursts as opposed to individual uncorrelated events. We are investigating the co-localization or clustering of active sites as a mechanism to control this effect and we attempt to reproduce these bursts through numerical simulation of transcription factors diffusing in a model yeast nucleus. We present a detailed introduction to the development of our computational model, as well as preliminary results describing the effect of clustering sites on transcriptional bursting.

Core faculty list

Core Faculty
PI Website Contact
Daniel I. Goldman http://crablab.gatech.edu daniel.goldman[at]physics.gatech.edu
Jennifer Curtis http://curtisresearch.gatech.edu/ jennifer.curtis[at]physics.gatech.edu
Kurt Wiesenfeld Department profile kurt.wiesenfeld[at] physics.gatech.edu
Joshua Weitz http://www.physics.gatech.edu/user/joshua-weitz jsweitz[at] gatech.edu
Harold Kim http://www.physics.gatech.edu/user/harold-kim harold.kim [at] physics.gatech.edu
David Hu http://www-old.me.gatech.edu/hu/ hu [at] me.gatech.edu

Support

This network is supported by the NSF Physics of Living Systems program within the physics division. The student research network is a part of the NSF Science across virtual institutes program to encourage interaction among researchers across many universities.

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