Meeting Abstract

P1.122  Sunday, Jan. 4  Novel splicing variation of a myostatin-like gene in the decapod crustacean, Gecarcinus lateralis COVI, JA*; MYKLES, DL; Colorado State Univ.; Colorado State Univ. joseph.covi@colostate.edu

Alternative splicing of myostatin transcripts is exceedingly rare. Myostatin-like genes have been identified in over one hundred species, but variation in mRNA splicing is only reported to occur in chicken and trout. We recently reported the identification of a myostatin-like gene in the blackback land crab, Gecarcinus lateralis. Sequencing of PCR products generated by rapid amplification of cDNA ends indicates that a single myostatin-like gene in the land crab is the subject of extensive alternative splicing. Clear splicing sites occur within the propeptide domain and 3 untranslated region. Both intron retention and alternative donor/acceptor sites occur alone or in combination to generate unique protein coding sequences that include a complete mature peptide domain. The mature peptide sequence for land crab is greater than 50% identical to that of mammalian myostatins and all nine conserved cysteines are present. At least two splice variants produce frame shifts that introduce premature stop codons in the propeptide domain. Interestingly, alternative splicing in the chicken also produces a transcript that encodes a truncated myostatin protein which lacks the mature peptide. The differential expression of a truncated myostatin-like gene in two disparate species suggests that the expression of a propeptide domain alone could have functional significance. All transcripts exhibit a broad tissue distribution, which suggests that the functional repertoire of the crustacean myostatin is more diverse than that of the mammalian protein. The predominant expression of myostatin-like transcripts in muscle tissue suggests that this TGF-Β factor plays a role in regulating muscle physiology in crustaceans. Supported by NSF IBN-0618203.