Meeting Abstract
The Y-organ (YO) is an endocrine gland that regulates molting in decapod crustaceans. The biosynthesis of ecdysteroids is negatively regulated by molt inhibiting hormone during intermolt and increased titers of circulating molting hormone triggers the animal to enter premolt. YO activation and commitment at early and mid premolt require mTOR and TGFβ/activin signaling, respectively. However, the roles of other signaling cascade(s) driving the production and inhibition of ecdysteroid biosynthesis are largely unknown. A transcriptomics approach was used to identify 1) known signal transduction pathway components, and 2) differentially expressed pathway components across molt cycle. An RNA-seq transcriptome was generated from 5 molt cycle stages (intermolt; early, mid, and late premolt; and postmolt) of Gecarcinus lateralis YO. The differential expression pipeline included removal of low counts; normalization of count data using RUVSeq, and identification of differentially expressed (DE) contigs using the limma-voom package. Following filtering and normalization, count data from 48,590 contigs were used to identify 14,791 DE contigs at <0.01 FDR cut-off. BLASTx against the KEGG Ortholog (KO) database using sequences from human, and six arthropod species resulted in annotation of pathway components. A total of 878 contigs with KO relevant to 23 signal transduction pathways were identified, of which 291 were DE. In addition to this, using Fisher’s exact test, 10 signaling KEGG pathways, including MAP kinase, mTOR, cAMP, Notch, Wnt, AMP kinase, were identified as significantly enriched at <0.05 FDR cut-off, implicating their role in regulating molt cycle stage transitions. Supported by NSF (IOS-1257732).
