Juvenile hormone regulation of the E75 nuclear receptor is conserved in Diptera and Lepidoptera.
Despite longstanding efforts, the juvenile hormone (JH) signaling pathway remains unknown. In Drosophila melanogaster (Diptera), JH activates expression of the E75A nuclear receptor. The E75 gene encodes a family of related proteins. A homologue of Drosophila E75 was previously identified and two isoforms, mE75A and mE75B, were reported in Manduca sexta (Lepidoptera). Here, we describe the identification of two additional isoforms, mE75C and mE75D, and the hormonal regulation of mE75 gene expression in Manduca CH1 cultured cells. mE75A and mE75B isoforms are specifically induced by ecdysone in CH1 cells. One isoform, mE75C, shows constitutive expression. The mE75D isoform exhibits dual hormonal regulation; it can be activated by either ecdysone or the JH analog, methoprene. E75-encoded proteins represent the first example of transcription factors directly induced by JH. E75 activation by JH, in both Diptera and Lepidoptera, suggests a conserved function in the JH signaling pathway.
Department of Biology, Dartmouth College, Hanover, NH 03755, USA.
Veronica A
VA
Dubrovskaya
Edward M
EM
Berger
Edward B
EB
Dubrovsky
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015152:Blotting, Northern; D002460:Cell Line; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000737:chemistry / Q000235:genetics; D004268:DNA-Binding Proteins / Q000235:genetics*; D004305:Dose-Response Relationship, Drug; D004331:Drosophila melanogaster / Q000235:genetics*; D004440:Ecdysone / Q000494:pharmacology; D005091:Exons; D015870:Gene Expression / Q000187:drug effects; D017344:Genes, Insect / Q000235:genetics; D019476:Insect Proteins / Q000235:genetics*; D007438:Introns; D007605:Juvenile Hormones / Q000494:pharmacology*; D018402:Manduca / Q000235:genetics*; D008726:Methoprene / Q000494:pharmacology; D008969:Molecular Sequence Data; D011987:Receptors, Steroid / Q000235:genetics*; D017422:Sequence Analysis, DNA; D013997:Time Factors; D014158:Transcription, Genetic / Q000187:drug effects
D018076:DNA, Complementary; D004268:DNA-Binding Proteins; C087173:E75 protein, insect; D019476:Insect Proteins; D007605:Juvenile Hormones; D011987:Receptors, Steroid; D004440:Ecdysone; D008726:Methoprene