Transcript 第35回北大MMCセミナーポスター

第35回
北大ＭＭＣセミナー
Date: 2015年1月23日（金）16:30～18:00
Speaker: 森下 喜弘(独立行政法人理化学研究所QBiC）
Place: 電子科学研究所 中央キャンパス総合研究棟2号館
5F北側講義室（北12条西7丁目）
Title: Coding Design of Positional Information for Robust
Morphogenesis and a theory on the timing of cell fate decision
in developing organs
Abstract: 別紙をご参照ください。
連絡先：
北海道大学 電子科学研究所
動的数理モデリング研究室
長山 雅晴 内線 3357
[email protected]
主催： 電子科学研究所 動的数理モデリング研究室
共催： 北海道大学数学連携研究センター
Abstract:
In this seminar, I will talk about two topics on mathematical approaches to
developmental biology.
(I) Robust positioning of cells in a tissue against unavoidable noises is
important for achieving normal and reproducible morphogenesis. The
position in a tissue is represented by morphogen concentrations, and
cells read them to recognize theirspatial coordinates. From the
engineering viewpoint, these positioning processes can be regarded as
an information coding. Organisms are conjectured to adopt good
coding designs with high reliability for a given number of available
morphogen species and their chemical properties. To answer,
quantitatively, the questions of how good coding is adopted, and
subsequently when, where, and to what extent each morphogen
contributes to positioning, we need a way to evaluate the goodness of
coding. In this article, by introducing basic concepts of computer
science, we mathematically formulate coding processes in
morphogendependent positioning, and define some key concepts such
as encoding, decoding, and positional information and its precision. We
demonstrate the best designs for pairs of encoding and decoding
rules, and show how those designs can be biologically implemented by
using some examples. We also propose a possible procedure of data
analysis to validate the coding optimality formulated here.
(II) Accurate patterning in developing tissues is one of the important
steps to achieve normal development. Differently from static
situations without tissue growth, relative positions of cells in growing
tissues dynamically changes. Cell trajectories in growing tissues
include different kinds of noises originating from the rearrangement of
cell positions through cell division and embryo-to-embryo variability
of tissue deformation dynamics itself. Such a kinematic randomness is
magnified by the growth of tissues, which can be a barrier for
achieving accurate spatial patterning in growing tissues. In this study,
from the theoretical side, we propose a design criterion about when
cell fates should be determined or when spatial patterning should be
done in growing tissues in the presence of kinematic randomness, and
apply the theory to chick limb developmental process.