Biophysical Society Newsletter - November 2016

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BIOPHYSICAL SOCIETY NEWSLETTER 6 NOVEMBER 2016
Biophysical Journal
Know the Editors
Andrew Spakowitz
Stanford University
Editor, Nucleic Acids and
Genome Biophysics
Q. What are you currently working on
that excites you?
My research group is focused on developing a
theoretical model of the physical segregation of
chromosomal DNA within the nucleus of a cell.
Densely packed regions of DNA (called hetero-
chromatin) have genes that are silenced. Whereas
more loosely packed regions (called euchromatin)
are able to express their coded proteins. This
physical segregation marks the transition from an
undifferentiated stem cell to a cell with a specific
identity. Therefore, this theoretical model aims to
capture a biological process that is fundamental
to our understanding of multicellular organisms.
Our model aims to address genomically relevant
length scales while accounting for the protein-
DNA interactions that drive condensation at the
molecular scale. Genomic DNA is an incredibly
long polymer, and capturing these multi-scale ef-
fects is not an easy task. The challenges associated
with bridging vast length scales of behavior are
similar to those faced by scientists and engineers
whose goal is to establish physical models of
conventional polymers. Thus, there is a wealth
of established approaches that can be leveraged,
adapted, and extended to develop a physics-based
model of chromosomal organization and dynam-
ics with predictive capabilities.
Q. What has been your most exciting
discovery as a biophysicist?
My work with Steph Weber, McGill University,
and Julie Theriot, Stanford University, led to the
discovery that the complex motion of chromo-
somal DNA within a bacterium can be captured
by extending a classical model for the motion of a
polymer molecule. This work bolsters our ap-
proach in modeling chromosomal DNA at vari-
ous coarse-grained levels with the hope of directly
engaging experimental measurements of in vivo
behavior.
Andrew Spakowitz
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