Morphogenetic cell movement in Dictyostelium

Dictyostelium morphogenesis starts with the chemotactic aggregation of star ving individual cells. The cells move in response to propagating waves of t he chemoattractant cyclic AMP initiated by cells in the aggregation centre. During aggregation the cells begin to differentiate into several types wit h different signalling and chemotactic properties. These cell types sort ou t from each other to form an axial pattern in the slug. There is now good e vidence that periodic chemotactic signals not only control aggregation, but also later stages of morphogenesis. These signals take the form of target patterns, spirals, multi-armed spirals and scroll waves. I will discuss the ir role in the control of cell movement during mound and slug formation and in the formation of the fruiting body.