Differential requirement of EGFR signaling for the expression of defective proventriculus gene in the Drosophila endoderm and ectoderm.
A homeobox gene, defective proventriculus (dve), is expressed in various tissues including the ventral ectoderm and midgut. Here, we show the expression pattern of dve in the ventral ectoderm, in which dve expression is induced by Spitz, a ligand for Drosophila epidermal growth factor receptor (EGFR). In spitz mutants, dve expression is only lost in the ventral ectoderm and overexpression of Spitz induces ectopic dve activation in the ventral ectoderm. Dve expression in the middle midgut depends on Decapentaplegic (Dpp) signaling, while expression of a dominant-negative form of Drosophila EGFR (DER(DN)) also causes a marked decrease in dve expression in the middle midgut. Furthermore, heterozygous mutation of thick veins (tkv), a Dpp receptor, strongly enhances the effect of DER(DN). These results indicate that EGFR signaling is crucial for dve expression in the ventral ectoderm and is required in the middle midgut where it cooperates with Dpp signaling.
Graduate School of Natural and Science Technology, Okayama University, 3-1-1 Tsushima-naka, Okayama 700-8530, Japan.
Tetsuya
T
Shirai
Atsushi
A
Maehara
Naruto
N
Kiritooshi
Fumio
F
Matsuzaki
Hiroshi
H
Handa
Hideki
H
Nakagoshi
D000818:Animals; D004330:Drosophila / Q000196:embryology* / Q000235:genetics / Q000378:metabolism*; D029721:Drosophila Proteins; D004475:Ectoderm / Q000378:metabolism*; D004707:Endoderm / Q000378:metabolism*; D004815:Epidermal Growth Factor; D066246:ErbB Receptors / Q000235:genetics / Q000378:metabolism*; D018507:Gene Expression Regulation, Developmental / Q000502:physiology*; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism*; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D014018:Tissue Distribution
D029721:Drosophila Proteins; D018398:Homeodomain Proteins; D008565:Membrane Proteins; C114494:dve protein, Drosophila; C076026:spi protein, Drosophila; D004815:Epidermal Growth Factor; D066246:ErbB Receptors