Studying apoptosis in the Zebrafish.

Zebrafish (Danio rerio) have been extensively used to study apoptotic cell death during normal development and under a wide range of experimental manipulations. A number of features make zebrafish a particularly powerful model organism: (1) embryos are small in size, develop rapidly outside the mother, and are optically transparent; (2) tools are readily available for rapid knockdown and overexpression of genes; and (3) embryos can be arrayed into multiwell plates and are permeable to a wide range of drugs and small molecules. The molecular machinery underlying the intrinsic and extrinsic apoptosis pathways appears to be highly conserved between zebrafish and mammals. In this chapter, techniques are described for detecting apoptotic cells in situ in both fixed and live zebrafish embryos. Methods for inducing and inhibiting apoptosis and for functionally manipulating genes involved in apoptotic signaling are also discussed.