Concanavalin A as a peripherally acting inhibitor of thyroxin-mediated metamorphosis in amphibians

Programmed cell death in the anuran tadpole tail requires expression of a cell surface glycoprotein

Programmed cell death is generally perceived as a suicide process involving activation of an internal death program thought to be common to all cells. We have previously presented evidence supporting the view that, at least in the tadpole tail, programmed cell death may involve assassination by cytotoxic cells such as resident macrophages. In this report, we show that regression of tadpole tail slices in culture is blocked by tunicamycin and brefeldin A, demonstrating that the intracellular protein trafficking machinery must be intact. Regression is also blocked by concanavalin A and fucose, suggesting a requirement for a cell surface glycoprotein. These observations are consistent with our hypothesis that programmed cell death requires expression of specific markers on the surfaces of cells destined to die, identifying the cells bearing those markers as targets for destruction.