Meeting Abstract

P2.137  Saturday, Jan. 5  Myostatin expression in the blackback land crab (Gecarcinus lateralis ) Y-organ during the molt cycle MUDRON, M.R.*; CHANG, E.S.; MYKLES, D.L.; Colorado State University; UC Davis Bodega Marine Laboratory; Colorado State University megan.mudron@gmail.com

Ecdysteroids produced from the molting gland (Y-organ or YO) induce molting in decapod crustaceans. Reduction in molting-inhibiting hormone (MIH) activates the YO and animals enter premolt. At mid-premolt, YOs transition to the committed state, in which ecdysteroid production increases further. In blackback land crab (Gecarcinus lateralis), SB1431542, an inhibitor of Activin receptors, decreases hemolymph ecdysteroid titers in premolt animals, suggesting that an Activin-like transforming-growth factor (TGF-β) is produced by the activated YO and drives the transition of the YO to the committed state. Myostatin (Gl-Mstn) is an Activin-like factor that is highly expressed in skeletal muscle. As Gl-Mstn is expressed in tissues in addition to muscle, the effects of molting on the Gl-Mstn expression in the YO were determined. Endpoint RT-PCR established that Gl-Mstn was expressed in the YO. Quantitative PCR was used to quantify the effects of molt induction by eyestalk ablation (ESA) on Gl-Mstn expression. YOs were harvested from intact (intermolt) animals and from animals at 1, 3, 7, and 14 days post-ESA. Gl-Mstn expression peaked at 3 days post-ESA (p = 0.025), which is before the transition to the committed state at 7 days post-ESA. Expression of elongation factor-2 (EF2) is significantly increased 7 days post-ESA (p = 0.014), indicating an increase in protein synthetic capacity. Future research will examine the regulation of Gl-Mstn by ecdysteroids. Supported by NSF (IOS-0745224).