Programmed cell death and patterning in Drosophila

Selective cell death provides developing tissues with the means to precisel y sculpt emerging structures. By imposing patterned cell death across a tis sue, boundaries can be created and tightened, As such, programmed cell deat h is becoming recognized as a major mechanism for patterning of a variety o f complex structures, Typically, cell types are initially organized into a fairly loose pattern; selective death then removes cells between pattern el ements to create correct structures. In this review, we examine the role of selective cell death across the course of Drosophila development, includin g the tightening of embryonic segmental boundaries, head maturation, refini ng adult structures such as the eye and the wing, and the ability of cell d eath to correct for pattern defects introduced by gene mutation. We also re view what is currently known of the relationship between signals at the cel l surface that are responsible for tissue patterning and the basal cell dea th machinery, an issue that remains poorly understood.