Origin and differentiation of supernumerary midline glia in Drosophila embryos deficient for apoptosis.
Drosophila embryos deficient for programmed cell death produce 9 midline glia (MG) in addition to the wild-type complement of 3.2 MG/segment. More than 3 of the supernumerary MG derive from the MGP (MG posterior) lineage and the remainder from the MGA/MGM (MG anterior and middle) lineage. There is one unidentified additional neuron in the mesectoderm of embryos deficient for apoptosis. The supernumerary MG are not diverted from other lineages nor do they arise from an altered pattern of mitosis. Instead, these MG appear to arise from a normally existing pool of 12 precursor cells, larger than anticipated by earlier studies. During normal development, MG survival is dependent upon signaling to the Drosophila EGF receptor. The persistence of supernumerary MG in embryos deficient for apoptosis does not alter the spatial pattern of Drosophila EGF receptor signaling. The number and position of MG which express genes dependent upon EGF receptor function, such as pointed or argos, are indistinguishable from wild type. Genes of the spitz group are required for Drosophila EGF receptor function. Surviving MG in spitz group/H99 double mutants continue to express genes characteristic of the MG, but the cells fail to differentiate into ensheathing glia and are displaced from the nerve cord.
Dong
R
R
Department of Biology, McMaster University, 1280 Main Street West, Hamilton, Ontario, L8S 4K1, Canada.
Jacobs
J R
JR
D000818:Animals; D017209:Apoptosis / Q000235:genetics*; D019521:Body Patterning; D002450:Cell Communication; D002452:Cell Count; D002454:Cell Differentiation; D019070:Cell Lineage; D004268:DNA-Binding Proteins; D004330:Drosophila / Q000196:embryology*; D029721:Drosophila Proteins; D004815:Epidermal Growth Factor; D066246:ErbB Receptors / Q000378:metabolism; D005136:Eye Proteins / Q000235:genetics; D017344:Genes, Insect; D008565:Membrane Proteins / Q000235:genetics; D009154:Mutation; D009417:Nerve Tissue / Q000196:embryology*; D009419:Nerve Tissue Proteins / Q000235:genetics; D009457:Neuroglia / Q000166:cytology*; D010455:Peptides / Q000235:genetics; D011518:Proto-Oncogene Proteins / Q000235:genetics; D013234:Stem Cells; D014157:Transcription Factors
D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D005136:Eye Proteins; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; D010455:Peptides; D011518:Proto-Oncogene Proteins; D014157:Transcription Factors; C083884:pnt protein, Drosophila; C086973:rpr protein, Drosophila; C075638:aos protein, Drosophila; C076026:spi protein, Drosophila; D004815:Epidermal Growth Factor; D066246:ErbB Receptors