Meeting Abstract
Crustacean molting is regulated by the interplay between inhibitory neuropeptides (MIH) secreted by the X organ located in the eyestalk (ES) and steroid hormones synthesized by the Y organ (YO). During intermolt, the YO maintains a basal state characterized by low ecdysteroid and high MIH titers. During early premolt, the YO transitions to an activated state characterized by a reduction in MIH titer, but retention of MIH sensitivity. mTOR signaling pathway genes are up regulated in early premolt- while rapamycin- which blocks mTOR signaling, has been shown to inhibit YO ecdysteriodogenesis. In G. lateralis, molt cycle entry was induced by eyestalk ablation (ESA). ESA animals were injected with either a single dose of rapamycin or DMSO carrier. Animals with intact eyestalks were examined as an intermolt control. YO tissue samples were harvested at 1, 3, and 7 days post-ESA and processed for RNA-seq on the Illumina platform. 224,631 contigs were obtained via Trinity de novo assembly; 31.92% of these could be assigned a SwissProt annotation. 51,408 differentially expressed genes (DEG) were identified using EdgeR with a 0.05 FDR cut-off. Rapamycin inhibits mTOR by complexing with FKBP12. DEG analysis revealed increased FKBP12 expression levels following rapamycin injection, with levels highest at day 7. A progressive decrease in the expression of mTOR pathway genes Akt, Rheb, EF2, S6K and PDK1 was observed, with Rheb and S6K showing minimal expression by day 7. Ecdysteroid pathway gene expression showed depressed levels relative to the DMSO datasets. A further detailed gene enrichment analysis is also in progress to evaluate DGEs downstream of the mTOR pathway. Supported by NSF (IOS-1257732).
