Meeting Abstract
Molting is necessary for growth and development in all arthropods. Halloween genes are expressed in the molting gland (Y-organ or YO) and encode enzymes that catalyze the synthesis of ecdysteroid hormones that coordinate molting processes during the premolt stage. mTOR activity is required for YO activation and entry into premolt. Transcriptomics was used to quantify gene expression in Gecarcinus lateralis induced to molt by multiple limb autotomy (MLA) or eyestalk ablation (ESA) ± mTOR inhibitor rapamycin. For the MLA transcriptome, relative mRNA levels of Halloween genes were highest in intermolt and early premolt and then decreased during mid and late premolt to their lowest levels 10 days postmolt. ESA/Rapamycin transcriptome showed that Halloween genes and ecdysone-responsive genes levels were not significantly different from control groups and experiment groups except HR4, which showed a transient increase at 1-day post-ESA. Using qPCR, ESA decreased mRNA levels of Halloween genes, Neverland and CYP18a1 at 3, 7, and 14 days post-ESA. Ecdysteroid receptor (EcR/RXR) binds active molting hormone, which induces serial activation of ecdysone-responsive genes. Insect gene sequences were used to identify contigs encoding Broad Complex, E75, E74, HR4, HR3, forkhead box transcription factor, and Fushi tarazu factor-1. The presence of EcR/RXR and ecdysone-responsive genes suggest that elevated ecdysteroid at the end of premolt and contributes to transcriptional inactivation in the repressed YO in postmolt. Supported by NSF (IOS-1257732).
