Control of spatial patterning and cell-type proportioning in Dictyostelium

The spatial patterning of prestalk and prespore cells in the slug arises fr om the differential sorting of newly differentiated cell tykes as the mound forms. This pattern is highly organized along an anterior-posterior axis a nd is constant irrespective of the size of the organism. Cell-type differen tiation is plastic until late in development. A change in the ratio of cell types resulting from removal of part of the slug leads to a rapid restorat ion of the original ratio of the cell types through a pathway involving ded ifferentiation, redifferentiation, and sorting of the existing cells. This review provides insight into various molecules, morphogens, and pathways re gulating spatial patterning and cell-type proportioning.