Meeting Abstract
The exoskeleton of arthropods must be shed for growth and development. In insects, the antagonistic signaling pathways between juvenile hormone (JH) and ecdysone regulate molting and metamorphosis. However, gene regulation of molting in crustaceans is not well understood. In insects, Krüppel homolog-1 (Kr-h1), a zinc finger transcription factor, is strongly induced by JH via the Met-SRC complex (methoprene tolerant-steroid receptor coactivator). When Kr-h1 directly binds to the promoter region of steroidogenic enzymes, methylation occurs thereby inhibiting ecdysone biosynthesis in the prothoracic gland (PG). As for crustaceans, Kr-h1 is involved in vitellogenesis in Portunus tritubulus and early development in Daphnia pulex while lacking JH responsiveness. As JH synthesis and ecdysteroidogenic genes are expressed in the crustacean molting gland (Y-organ), we hypothesize that Kr-h1 may act in the Y-organ analogous to that in the PG. In G. lateralis molting can be either induced by multiple leg autonomy (MLA) or eyestalk ablation (ESA), which removes the source of molt-inhibiting hormone (MIH). By using transcriptomic data of MLA and ESA G. lateralis individuals, Kr-h1 homologs were identified: two gene products were obtained from the MLA transcriptome and one gene product from the ESA transcriptome. The deduced proteins all had the seven zinc finger repeats that are characteristic of insect Kr-h1 who have eight repeats. Quanitative PCR will be used to quantify the effects of MLA and ESA on Kr-h1 mRNA levels in the Y-organ. Supported by NSF (IOS-1257732).
