Misexpression of the eyes absent family triggers the apoptotic program.
Genetic studies in Drosophila and mice have shown that eyes absent (eya) is an important and conserved transcriptional regulator of development. Along with eyeless/Pax6, sine oculis, and dachshund, eya genes function as master regulators in eye development and can induce ectopic eye formation. Furthermore, the loss-of-function mutants of these genes in the fly causes partial or complete loss of the compound eye, and this is associated with inappropriate apoptosis. Conversely, ectopic eyeless expression in the context of eyes absent or sine oculis mutations results in apoptosis, suggesting that the proper ratio of these factors regulates apoptosis. Here we report that enforced expression of fly eya or of one of its mammalian homologs, Eya2, triggers rapid apoptosis in interleukin-3-dependent 32D.3 murine myeloid cells, which express Eya family members but not Pax6. Eya-induced cell death overrides survival factors and has many features typical of apoptosis, including plasma and mitochondrial membrane changes and caspase activation. Eya-induced apoptosis is blocked by Bcl-2 overexpression but not by the broad-spectrum caspase inhibitor z-VAD.fmk, suggesting that mitochondria are a major target in Eya-induced apoptosis. These results support the concept that inappropriate changes in the steady state levels of Eya proteins may trigger programmed cell deaths during development.
Clark
S Wesley
SW
Department of Biochemistry, St. Jude Children's Research Hospital, Memphis, Tennessee 38105, USA.
Fee
Brian E
BE
Cleveland
John L
JL
D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D016923:Cell Death / Q000502:physiology; D002460:Cell Line; D002462:Cell Membrane / Q000502:physiology; D002470:Cell Survival / Q000502:physiology; D003001:Cloning, Molecular; D017931:DNA Primers; D003907:Dexamethasone / Q000494:pharmacology; D004330:Drosophila / Q000196:embryology; D029721:Drosophila Proteins; D004622:Embryo, Mammalian; D004625:Embryo, Nonmammalian; D020224:Expressed Sequence Tags; D005123:Eye / Q000166:cytology / Q000196:embryology*; D005136:Eye Proteins / Q000235:genetics*; D006801:Humans; D008564:Membrane Potentials; D051379:Mice; D018613:Microscopy, Confocal; D008928:Mitochondria / Q000502:physiology; D009154:Mutation; D009687:Nuclear Proteins / Q000235:genetics; D020319:Oligodeoxyribonucleotides, Antisense; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction
D017931:DNA Primers; D029721:Drosophila Proteins; D005136:Eye Proteins; D009687:Nuclear Proteins; D020319:Oligodeoxyribonucleotides, Antisense; D019253:Proto-Oncogene Proteins c-bcl-2; C092694:eya protein, Drosophila; D003907:Dexamethasone