YANG Laboratory

Biophysics of Living Systems

Research

The broad focus of the Yang lab is on the quantitative understanding of early embryo development, a complex pattern formation process that involves proliferation, differentiation, and migration of indivldual cells, and cell-cell communications through mechanical and chemical signaling. Our strategy is to connect these multi-scale mechanisms by developing complementary in vitro and in vivo systems in the vertebrate zebrafish (Danio rerio) embryos.

Cell-Free System

The cell-free system we develop is based on embryo or egg extracts, which are amenable to quantitative biochemical assays and manipulations. We use cell-free extracts to reconstitute dynamic events that exist in intact embryos but with reduced essential components. We further encapsulate these active extracts in droplet-based microfluidic chambers for closer manipulations both biochemically and mechanically. In addition, we synthesize biological circuits of new functions using protein engineering. Our current focus is to understand the synchronized cell division cycles in early vertegrate embryos of zebrafish and Xenopus. Since we only extract the relatively transparent cytosol part of embryos, the cell-free system better suits for tracking molecular events at the single molecule level.

Live Embryos

We use zebrafish live embryos, as a system complementary to cell-free extracts, to allow for real-time, multi-scale investigation of developmental processes. We apply the "in toto imaging" technique that is originally developed by Sean Megason's laboratory at Harvard, to track each single cell's 'fate' as the cells divide, differentiate, move and interact. With mathematical modeling, we set to find out how these cellular behaviors give rise to the tissue level patterns and eventually develop into the organism. Currently, we focus on the interplay of several biological clocks, namely mitotic oscillators and segmentation clocks, that play essential roles in somite pattern formation of early vertebrate embryos.