title: Drosophila eggshell production: identification of new genes and coordination by Pxt.
abstract: Drosophila ovarian follicles complete development using a spatially and temporally controlled maturation process in which they resume meiosis and secrete a multi-layered, protective eggshell before undergoing arrest and/or ovulation. Microarray analysis revealed more than 150 genes that are expressed in a stage-specific manner during the last 24 hours of follicle development. These include all 30 previously known eggshell genes, as well as 19 new candidate chorion genes and 100 other genes likely to participate in maturation. Mutations in pxt, encoding a putative Drosophila cyclooxygenase, cause many transcripts to begin expression prematurely, and are associated with eggshell defects. Somatic activity of Pxt is required, as RNAi knockdown of pxt in the follicle cells recapitulates both the temporal expression and eggshell defects. One of the temporally regulated genes, cyp18a1, which encodes a cytochromome P450 protein mediating ecdysone turnover, is downregulated in pxt mutant follicles, and cyp18a1 mutation itself alters eggshell gene expression. These studies further define the molecular program of Drosophila follicle maturation and support the idea that it is coordinated by lipid and steroid hormonal signals.
authors.affiliation: Department of Anatomy and Cell Biology, Roy J. and Lucille Carver College of Medicine, University of Iowa, Iowa City, Iowa, United States of America. tina-tootle@uiowa.edu
authors.forename: Tina L
authors.initials: TL
authors.lastname: Tootle
authors.forename: Dianne
authors.initials: D
authors.lastname: Williams
authors.forename: Alexander
authors.initials: A
authors.lastname: Hubb
authors.forename: Rebecca
authors.initials: R
authors.lastname: Frederick
authors.forename: Allan
authors.initials: A
authors.lastname: Spradling
mesh_terms: D000818:Animals; D002823:Chorion / Q000378:metabolism; D003577:Cytochrome P-450 Enzyme System / Q000235:genetics / Q000378:metabolism; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000196:embryology / Q000235:genetics*; D004625:Embryo, Nonmammalian / Q000166:cytology / Q000378:metabolism; D005260:Female; D020869:Gene Expression Profiling; D018507:Gene Expression Regulation, Developmental; D017344:Genes, Insect / Q000235:genetics*; D009154:Mutation / Q000235:genetics; D006080:Ovarian Follicle / Q000166:cytology / Q000196:embryology / Q000254:growth & development; D010063:Ovum / Q000166:cytology / Q000378:metabolism*; D010544:Peroxidases / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D013997:Time Factors
chemical_list: D029721:Drosophila Proteins; D012333:RNA, Messenger; D003577:Cytochrome P-450 Enzyme System; C554287:ecdysteroid 26-hydroxylase, Drosophila; D010544:Peroxidases; C529210:Pxt protein, Drosophila