Meeting Abstract

S3.2-1  Saturday, Jan. 4 10:30  Using C. elegans and other organisms to understand conserved mechanisms of morphogenesis GOLDSTEIN, Bob; University of North Carolina, Chapel Hill bobg@unc.edu

Apical constriction changes cell shapes, driving fundamental morphogenetic events, including gastrulation in diverse organisms and neural tube closure in vertebrates. Apical constriction is thought to be triggered by contraction of apical actomyosin networks. I will present results from my lab showing that such actomyosin contractions begin before cell shape changes in both C. elegans and Drosophila, demonstrating that such contractions must not be not sufficient for cell shape change. In C. elegans, actomyosin networks were initially dynamic, contracting and generating significant cortical tension without substantial shrinking of apical surfaces. Apical cell-cell contact zones and actomyosin only later move increasingly in concert, with no detectable change in actomyosin dynamics or in cortical tension. Thus, apical constriction appears to be triggered not by a change in cortical tension, but by dynamic linking of apical cell-cell contact zones to an already contractile apical cortex. I will also present our work seeking to identify molecular mechanisms of cell shape change that have been conserved across the bilaterally symmetrical animals.