Martin Lab

During development, individual cell shape changes and movements collectively sculpt tissues into organs with precise forms and functions in a process called tissue morphogenesis. Tissue morphogenesis requires that forces are generated at the molecular, cellular, and tissue levels. However, the molecular mechanisms that generate forces are not known for many of the cell shape changes and movements that underlie morphogenesis. Furthermore, how cell shape changes and cellular forces are coordinated across a tissue to achieve morphogenesis is an important unanswered question in biology.

In the Martin lab, we are interested in how forces are generated and transmitted across multiple length scales during embryonic development. We study these questions using the fruit fly, Drosophila melanogaster, where cell shape changes and cytoskeletal dynamics can be readily imaged by confocal microscopy and quantified using computational approaches. This quantitative live imaging can be combined with genetic (mutants, RNAi), cell biological (drug injections), biophysical (laser cutting), and biochemical (complex purification, reconstitution) approaches to functionally dissect cell shape change in the embryo. We encourage students and postdocs with either experimental or computational backgrounds to inquire about our lab.

Professor Martin's lab uses Drosophila gastrulation as a model system to examine the forces that are generated during cell shape change and tissue morphogenesis. Gastrulation is a dramatic developmental event, with masses of cells undergoing collective movements in order to organize the embryo into the three separate germ layers that will give rise to different parts of the body. We focus on a cell shape change that accompanies gastrulation in many organisms, apical constriction. Apical constriction converts columnar shaped epithelial cells to wedge or cone shaped cells, which facilitates epithelial folding and tissue invagination. In Drosophila, apical constriction is required for the invagination of the prospective mesoderm, a strip of ~1200 cells along the ventral midline of the embryo. Apical constriction was widely believed to result from the purse-string-like contraction of a circumferential actin and myosin II (myosin) belt that directly underlies adherens junctions.