title: The 20-hydroxyecdysone-induced signalling pathway in G2/M arrest of Plodia interpunctella imaginal wing cells.
abstract: The mechanisms involved in the control of cellular proliferation by the steroid hormone 20-hydroxyecdysone (20E) in insects are not known. We dissected the 20E signalling pathway responsible for G2/M arrest of imaginal cells from the IAL-PID2 cells of the Indian meal moth Plodia interpunctella. We first used a 5'-3' RACE-based strategy to clone a 4479bp cDNA encoding a putative P. interpunctella HR3 transcription factor named PiHR3. The deduced amino acid sequence of PiHR3 was highly similar to those of HR3 proteins from other lepidopterans, e.g. Manduca sexta and Bombyx mori. Using double-stranded RNA-mediated interference (dsRNAi), we then succeeded in blocking the ability of 20E to induce the expression of PiEcR-B1, PiUSP-2 and PiHR3 genes that encode the P. interpunctella ecdysone receptor B1-isoform, Ultraspiracle-2 isoform, the insect homologue of the vertebrate retinoid X receptor, and the HR3 transcription factor. We showed that inhibiting the 20E induction of PiEcR-B1, PiUSP-2 and PiHR3 mRNAs prevented the decreased expression of B cyclin and consequently the G2/M arrest of IAL-PID2 cells. Using this functional approach, we revealed the participation of EcR, USP and HR3 in a 20E signalling pathway that controls the proliferation of imaginal cells by regulating the expression of B cyclin.
authors.affiliation: UMR 1272A Physiologie de l'Insecte, Signalisation et Communication, Université Pierre et Marie Curie, 7 quai Saint Bernard, 75005 Paris, France.
authors.forename: David
authors.initials: D
authors.lastname: Siaussat
authors.forename: Françoise
authors.initials: F
authors.lastname: Bozzolan
authors.forename: Patrick
authors.initials: P
authors.lastname: Porcheron
authors.forename: Stéphane
authors.initials: S
authors.lastname: Debernard
mesh_terms: D000818:Animals; D002453:Cell Cycle / Q000502:physiology; D002460:Cell Line; D049109:Cell Proliferation; D019926:Cyclin B / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D029721:Drosophila Proteins; D004441:Ecdysterone / Q000378:metabolism*; D008675:Metamorphosis, Biological / Q000502:physiology*; D009036:Moths / Q000235:genetics / Q000378:metabolism*; D011987:Receptors, Steroid / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D014921:Wings, Animal / Q000254:growth & development
chemical_list: D019926:Cyclin B; D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D011987:Receptors, Steroid; D014157:Transcription Factors; C066030:USP protein, Drosophila; C055469:ecdysone receptor; D004441:Ecdysterone