研究/Research研究/Research
Physics of living matters and Origin of life
Living cell can be described as a self-reproducing automata: a simple machine encapsulates genetic information (= tape), transcription and translation machines (= the universal constructor), and the replication machine (= the copier) (see the figure below). Advances in molecular biology and condensed matter physics enable us to demonstrate this consept in the experimental physics, not only in mathematics. The goal of my study is to understand physical principles of a self-reproducing cell. This study will allow us to know how primitive life originates from the cocktail of macromolecules and give the one possible definition of life.
研究分野/Fields of study
Physics of living matters, Systems biology
プロジェクト/Projects
1. Synthetic self-reproduction as a step toward artificial cells
Protocell might be simple but be still complex to show elemental properties of living cells. In that context a protocell able to self-reproduce has to express genetic information and to replicate itself. Recent study has shown that the cell free extract can be encapsulated in vesicles and long-lasting gene expression is sustained by the exchange of small molecules such as amino acids. The next step toward the realization of artificial protocell is to build replication machinery that is responsible for cell division and replication of genomic DNA. To address this issue, I employ soft-condensed matter physics and aim to understand physical and chemical principles for self-reproduction in simplified biological systems. I am currently working on
Synthesis and manipulation of minimal cell division machinery
Synthesis of minimal DNA/RNA replication systems
2. Physics of living matters in rewired and rebuilt systems in vivo
Living cells, even bacteria, are infinitely complicated. I try to avoid this complexity by means of the replacement of a inherited system with synthesized one.This rewired system is well-defined and thus enables us to employ physical analysis at a cellular level. I observe spatio-temporal dynamics of rewired systems in vivo in order to understand physical principle of cell division, cell polarity, and other phenomena through quantitative analysis.
In different context, I am interested in dynamics of cell migration as a stochastic process. An amoeba cell of Dictyostelium discoideum can sense the gradient of some chemicals (food, cAMP, etc) and move toward the source of those attractants. This behavior is called as chemotaxis. On the other hand, the cell shows spontaneous cell migration (SCM) in the absence of attractants. My previous work has shown that the fundamental mechanism of SCM is the coordination between the ordered pattens of cell shape and cell movement (Maeda YT, et al. 2008). This coordination is mediated by the circuit of PI3-kinase(PI3K)/PTEN/filamentous actin(F-actin). I am interested in the relationship between the fluctuation of PI3K/PTEN/F-actin observed in SCM and the accuracy of chemotaxis. In order to address this issue, I am studying the theoretical model of SCM and aim to experimentally demonstrate underlying principles from the view point of statistical physics. Collaborator: Dr, Miki Y. Matsuo
and more... Gene regulatory circuits, Traction force microscopy, Bacterial collective motion
