The glial cell undergoes apoptosis in the microchaete lineage of Drosophila.
Apoptosis plays a major role in vertebrate and invertebrate development. The adult Drosophila thoracic microchaete is a mechanosensory organ whose development has been extensively studied as a model of how cell division and cell determination intermingle. This sensory organ arises from a cell lineage that produces a glial cell and four other cells that form the organ. In this study, using an in vivo approach as well as fixed material, we show that the glial cell undergoes nucleus fragmentation shortly after birth. Fragmentation was blocked after overexpression of the caspase inhibitor p35 or removal of the pro-apoptotic genes reaper, hid and grim, showing that the glial cell undergoes apoptosis. Moreover, it seems that fragments are eliminated from the epithelium by mobile macrophages. Forcing survival of the glial cells induces precocious axonal outgrowth but does not affect final axonal patterning and connectivity. However, under these conditions, glial cells do not fragment but leave the epithelium by a mechanism that is reminiscent of cell competition. Finally, we present evidences showing that glial cells are committed to apoptosis independently of gcm and prospero expression. We suggest that apoptosis is triggered by a cell autonomous mechanism.
Fichelson
Pierre
P
UMR 7622, CNRS-Université Paris VI, 9, Quai St Bernard, 75252 Paris Cedex 05, France.
Gho
Michel
M
D000818:Animals; D030801:Animals, Genetically Modified; D000831:Animals, Newborn; D017209:Apoptosis / Q000502:physiology*; D001369:Axons / Q000502:physiology; D019070:Cell Lineage; D002470:Cell Survival; D015853:Cysteine Proteinase Inhibitors / Q000235:genetics; D004268:DNA-Binding Proteins; D004330:Drosophila / Q000235:genetics / Q000254:growth & development*; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism; D004847:Epithelial Cells; D004848:Epithelium / Q000254:growth & development; D018507:Gene Expression Regulation, Developmental; D051034:Inhibitor of Apoptosis Proteins; D018613:Microscopy, Confocal / Q000379:methods; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism; D009457:Neuroglia / Q000166:cytology*; D009479:Neuropeptides / Q000235:genetics / Q000378:metabolism; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D010587:Phagocytosis / Q000502:physiology; D011679:Pupa; D012679:Sense Organs / Q000166:cytology* / Q000254:growth & development*; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism; D014157:Transcription Factors; D014764:Viral Proteins / Q000235:genetics
D015853:Cysteine Proteinase Inhibitors; D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; C102805:GCM protein, Drosophila; C108880:HID protein, Drosophila; D051034:Inhibitor of Apoptosis Proteins; D009419:Nerve Tissue Proteins; D009479:Neuropeptides; D009687:Nuclear Proteins; D015534:Trans-Activators; D014157:Transcription Factors; D014764:Viral Proteins; C086430:inhibitor of apoptosis, Nucleopolyhedrovirus; C073099:pros protein, Drosophila; C086973:rpr protein, Drosophila