title: Temporal profiles of nuclear receptor gene expression reveal coordinate transcriptional responses during Drosophila development.
abstract: The recent completion of the Drosophila genome sequence revealed 21 members of the nuclear receptor superfamily. Many of these genes are transcriptionally regulated by the steroid hormone ecdysone and play a role during the onset of metamorphosis, including the EcR/USP ecdysone receptor heterodimer. As a first step toward a genomic analysis of this gene family, we have characterized the temporal patterns of expression for all detectable nuclear receptor transcripts throughout major ecdysone-regulated developmental transitions in the life cycle: embryogenesis, a larval molt, puparium formation, and the prepupal-pupal transition. We find an unexpected close temporal relationship between DHR3, E75B, and betaFTZ-F1 expression after each major ecdysone pulse examined, reflecting the known cross-regulatory interactions of these genes in prepupae and suggesting that they act together at other stages in the life cycle. In addition, E75A, E78B, and DHR4 are expressed in a reproducible manner with DHR3, E75B, and betaFTZ-F1, suggesting that they intersect with this regulatory cascade. Finally, we find that known ecdysone-inducible primary-response transcripts are coordinately induced at times when the ecdysteroid titer is low, implying the existence of novel, as yet uncharacterized, temporal signals in Drosophila.
authors.affiliation: Howard Hughes Medical Institute, Department of Human Genetics, University of Utah School of Medicine, University of Utah, Salt Lake City, Utah 84112-5331, USA.
authors.forename: April A
authors.initials: AA
authors.lastname: Sullivan
authors.forename: Carl S
authors.initials: CS
authors.lastname: Thummel
mesh_terms: D000818:Animals; D015152:Blotting, Northern; D004330:Drosophila / Q000196:embryology / Q000235:genetics* / Q000254:growth & development*; D004440:Ecdysone / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D007814:Larva / Q000235:genetics / Q000254:growth & development; D008675:Metamorphosis, Biological; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D018160:Receptors, Cytoplasmic and Nuclear / Q000235:genetics*; D013997:Time Factors; D014158:Transcription, Genetic / Q000235:genetics*
chemical_list: D012333:RNA, Messenger; D018160:Receptors, Cytoplasmic and Nuclear; D004440:Ecdysone