The hierarchical relationship among the spitz/Egfr signaling genes in cell fate determination in the Drosophila ventral neuroectoderm.
The spitz class and Egfr signaling (spi/Egfr) genes are required for the proper establishment of cell fate in the Drosophila ventral neuroectoderm. We investigated the role of the central nervous system (CNS) midline cells, and the hierarchical relationship among the spi/Egfr genes, in this process by analyzing the spatial and temporal expression of several of the genes in selected spi/Egfr mutants. Our analysis showed that expression of all the spi/Egfr genes is severely reduced in the single-minded (sim) mutant, and ectopically induced in en-Gal4/UAS-sim embryos. This result indicates that sim acts upstream of all the other spi/Egfr genes. The CNS midline cells regulate rhomboid (rho) expression in the ventral neuroectoderm and activate the EGFR signaling pathway. We also found that argos (aos) and orthodenticle (otd) act downstream of pointed (pnt), and that aos represses expression of otd in the lateral neuroectoderm to establish differential cell fates in the ventral neuroectoderm. Our findings suggest the following hierarchical relationship among the spi/Egfr genes: [see text].
Chang
Jinsook
J
Department of Chemistry, Konkuk University, Seoul 143-701, Korea.
Jeon
Sang-Hak
SH
Kim
Sang Hee
SH
D000818:Animals; D051792:Basic Helix-Loop-Helix Proteins; D019521:Body Patterning / Q000235:genetics / Q000502:physiology; D004268:DNA-Binding Proteins / Q000378:metabolism; D004330:Drosophila / Q000196:embryology*; D029721:Drosophila Proteins / Q000378:metabolism; D004475:Ectoderm / Q000502:physiology; D004815:Epidermal Growth Factor; D066246:ErbB Receptors / Q000235:genetics / Q000378:metabolism*; D018507:Gene Expression Regulation, Developmental / Q000502:physiology; D018773:Genes, erbB-1; D018398:Homeodomain Proteins / Q000378:metabolism; D008565:Membrane Proteins / Q000235:genetics* / Q000378:metabolism; D009419:Nerve Tissue Proteins; D009687:Nuclear Proteins / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology*; D014157:Transcription Factors
D051792:Basic Helix-Loop-Helix Proteins; D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D004815:Epidermal Growth Factor; D066246:ErbB Receptors; D018398:Homeodomain Proteins; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; D009687:Nuclear Proteins; D011518:Proto-Oncogene Proteins; D014157:Transcription Factors; C081481:Rho protein, Drosophila; C093053:oc protein, Drosophila; C083884:pnt protein, Drosophila; C089449:sim protein, Drosophila; C076026:spi protein, Drosophila