SEX-SPECIFIC AND HORMONE-CONTROLLED EXPRESSION OF A VITELLOGENIN-ENCODING GENE IN THE GYPSY-MOTH

Microvitellogenin and vitellogenin cDNA from Manduca sexta (tobacco ho rnworm) were tested for use as molecular probes to investigate the exp ression of genes coding for vitellogenins in Spodoptera frugiperda (fa ll armyworm) and Lymantria dispar (gypsy moth). Cross-hybridization wa s not observed between the M. sexta cDNAs and S. frugiperda DNA and mR NA. Vitellogenin cDNA from M. sexta did not hybridize to L. dispar DNA or mRNA. However, the 834 bp microvitellogenin cDNA from M. sexta hyb ridized to an approximately 850 bp transcript in L. dispar mRNA. A 2.5 kb cDNA clone, pz64, was isolated from late last instar larvae of fem ale L. dispar by differential screening. This clone has 38% amino acid sequence (deduced) and 55% nucleic acid sequence similarities with th e 3'-end of high molecular weight vitellogenin in Bombyx mori (silkwor m). When used as a probe in northern analysis of L. dispar mRNA, this cDNA hybridized to a 5.3 kb transcript in female last instar larvae, p upae, and adults, but not to male last instar larvae and adults. This cDNA did not hybridize to mRNA from M. sexta or S. frugiperda. Express ion of the 5.3 kb vitellogenin transcript hybridizing to the 2.5 kb cD NA clone was suppressed in 5-day-old last instar larvae of female L. d ispar treated on day 2 with doses of the juvenile hormone analog, meth oprene, greater than 10 nmol. Apparently, the high in vivo titer of ju venile hormone during the first 2 days of the last instar represses th e transcription of vitellogenin mRNA. (C) 1996 Wiley-Liss, Inc.