Differentially expressed genes in metamorphosis and after juvenile hormone application in the pupa of Galleria

Abstract

In Galleria mellonella, the pupal–adult transformation of epidermal cells is initiated at day 1 after pupal ecdysis by downregulation of pupal syntheses and loss of juvenile hormone (JH) sensitivity, indicating the change from pupal to adult commitment. To trace regulatory events as close as possible to the early steps of this process, we have analyzed, by differential display, changes in epidermal mRNA populations during the first day after pupal ecdysis in normal development as well as after JH injection. We isolated and cloned 20 cDNA 3′-fragments that are differentially expressed with regard to their developmental profile either in normal development or after injection of JH. Four clones could be verified by Northern blot hybridization. Screening of corresponding cDNA libraries with digoxigenin-labeled anti-sense mRNA probes yielded two full-length cDNA clones (9/27 and 23/86). Both of them represent genes that could be involved in the regulatory events during initiation of pupal metamorphosis or in the action of JH, respectively. The 9/27 mRNA is inducible by JH. It contains, in the 3′ untranslated region, a consensus sequence for deadenylation and specific degradation. The corresponding protein possesses two PKC phosphorylation sites and is with high probability a nuclear protein. The 23/86 clone represents polyubiquitin, differentially regulated in normal development and after JH application.