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来る11/20に東大薬学部遺伝学教室ではThomas Gregor博士

“Physical constraints and limits to precision in early
embryonic development”

Dr. Thomas Gregor

JSPS&s_comma; PhD fellow&s_comma; the University of Tokyo&s_comma; Graduate School of Arts
and Sciences&s_comma; Department of Basic Science/ Princeton University

During embryonic development&s_comma; information about spatial location is
represented by the concentration of various protein gradients. The
reproducibility and precision of biological pattern formation is thus
limited by the accuracy with which these concentration profiles can
be established and “read out” by their target pathways.
In this talk&s_comma; I present a biophysical analysis of one of the most
studied protein gradients in the fruit fly embryo&s_comma; the Drosophila
Bicoid morphogen gradient. First&s_comma; using two-photon microscopy and
other biophysical instrumentation techniques&s_comma; both the full
spatiotemporal dynamics that lead to gradient establishment and the
gradient’s scaling with embryo size in closely-related species were
measured and used to test a simple physical model. Second&s_comma; four
functionally different measurements of precision for the protein
gradient were considered; through a combination of different
experiments&s_comma; I showed that all of these quantities are ~10%&s_comma; which is
close to the physical limit set by random arrival of individual
molecules at their targets. The agreement among the different
measures of accuracy indicates that the system in fact relies on
precise control of absolute concentrations&s_comma; and responds reliably to
small changes in these concentrations&s_comma; down to the limits set by
basic physical principles. This contradicts previous research&s_comma; which
was driven by the assumption that sloppy input signals and noisy
readout mechanisms govern embryonic development.

Gregor T&s_comma; Tank DW&s_comma; Wieschaus EF&s_comma; Bialek W. Probing the limits to
positional information. Cell. 130:153-64&s_comma; 2007
Gregor T&s_comma; Wieschaus EF&s_comma; McGregor AP&s_comma; Bialek W&s_comma; Tank DW. Stability and
nuclear dynamics of the bicoid morphogen gradient. Cell. 130:141-52&s_comma;

【紹介記事 】
Matthew C. Gibson. Bicoid by the Numbers: Quantifying a Morphogen
Gradient. Cell. 130:14-16&s_comma; 2007.

時間: 16:30-17:30

連絡先:薬学部遺伝学教室 三浦正幸(内線24860)


山口良文 Yoshifumi Yamaguchi&s_comma; Ph.D
〒113-0033 東京都文京区本郷7-3-1 東京大学大学院薬学
Department of Genetics&s_comma; Graduate School of Pharmaceutical Sciences&s_comma;
University of Tokyo&s_comma; 7-3-1 Hongo&s_comma; Bunkyo-ku&s_comma; Tokyo 113-0033&s_comma; Japan
Phone: +81-3-5841-4863 Fax:+81-3-5841-4867
E-mail: bunbun@mol.f.u-tokyo.ac.jp