Meeting Abstract
In Gecarcinus lateralis, molting is stimulated by ecdysteroids, hormones produced in the Y-organ (YO). Animals spend a majority of time in the intermolt stage, when hemolymph ecdysteroid levels are low; the YO is in the basal state. In preparation for molting, the YO becomes activated; ecdysteroid titers increase and the animal enters the premolt stage, which is comprised of three substages: early premolt, mid premolt, and late premolt. At mid premolt the YO transitions to the committed state and ecdysteroid titers reach a peak in late premolt. To better understand the genetic networks that drive the YO through the basal, activated, and committed states, a transcriptome from intermolt and the three premolt substages was generated. Following Illumina sequence a reference transcriptome was assembled de novo using trimmed reads. Sequences were annotated using BLASTx against the NR and Swissprot databases. Expression levels for each sequence were calculated by mapping reads from each library to the reference transcriptome. To validate the reference transcriptome, we compared genes identified in G. lateralis using traditional sequencing to transcriptome sequences using local BLAST searches. Gl-Rheb, Gl-mTOR, Gl-S6K, and Gl-Akt were present in the transcriptome with over 99% similarity to genes obtained through traditional sequencing. These genes are components of the mechanistic target of rapamycin pathway (mTOR), which is required for sustained YO ecdysteroidogenesis. Relative expression analysis is being used to identify genes characteristic of each of the YO physiological state. Supported by NSF (IOS-1257732).
