Meeting Abstract

P1.63  Wednesday, Jan. 4  Cloning and Characterization of a Novel Transforming Growth Factor-β in Crustaceans ECHLIN, ML*; MACLEA, KS; MYKLES, DL; Colorado State Univ.; Colorado State Univ.; Colorado State Univ. moriahe@rams.colostate.edu

The molting gland, or Y-organ (YO), of decapod crustaceans transitions through four physiological states (basal, activated, committed, and repressed) during the molt cycle. We hypothesize that a TGF-&beta-like factor is required for the YO to transition from the activated to the committed state during premolt. TGF-β is an autocrine factor that controls cell proliferation and differentiation in mammals. In YO, TGF-β may alter molt-inhibiting hormone (MIH) and metazoan Target of Rapamycin (mTOR) signaling pathways to stimulate ecdysteroid synthesis. The only members of the TGF-β superfamily that have been characterized in crustaceans are cDNAs encoding myostatin (Mstn). A BLAST search of the GenBank database identified an expressed sequence tag (EST; 1.7 kb; accession #CN854252) of a TGF-β factor distinct from Mstn in the American lobster, Homarus americanus. The EST was obtained from a library constructed from mixed tissues at Mount Desert Island Biological Lab by David Towle and Chris Smith and was fully sequenced. The deduced amino acid sequence has 52-75% identity and 73-85% similarity to the mature peptide domain of TGF-&beta-like factors in other arthropods. Furthermore, a sequence alignment shows highly conserved regions in the mature peptide domain, including the 7 cysteines involved in intra- and inter-molecular disulfide bridges. We will use 5’ rapid amplification of cDNA ends (RACE) to extend the lobster sequence and polymerase chain reaction (PCR) and RACE to clone the ortholog from the blackback land crab, Gecarcinus lateralis. A goal is to quantify the effects of molting on the expression of TGF-β in the YO using quantitative PCR. Supported by NSF (IOS-0745224).