Meeting Abstract

P1.120  Sunday, Jan. 4  Troponin-C cloning and tissue expression in the American lobster, Homarus americanus CHAO, Erica*; KIM, Hyun-Woo; THOMPSON, Matthew D; MYKLES, Donald L; Colorado State University; Colorado State University; Colorado State University; Colorado State University

Troponin-C (Tn-C) regulates muscle contraction by binding calcium. Three Tn-C isoforms have been identified in lobster (Tn-C1, Tn-C2a and Tn-C2b) and have previously been sequenced at the amino acid (aa) level. We cloned the full-length nucleotide (nt) sequence of Tn-C1 (679 kb, 150 aa, 17.0 kDa), a partial sequence coding for Tn-C2a, and four full-length nucleotide sequences coding for novel lobster Tn-C isoforms designated Tn-C3 (1128 kb, 150 aa, 16.9 kDa), Tn-C4 (733 kb, 108 aa, 12.1 kDa), Tn-C5 (2884 kb, 149 aa, 17.3 kDa) and Tn-Cx (2242 kb, 154 aa, 16.9 kDa). The former four sequences were found via RT- and RACE-PCR; the latter two were ESTs sequenced via RT-PCR. The translated aa sequence of Tn-C4 was N-terminally truncated (38 aa). Tn-Cx was highly divergent from the other lobster Tn-C sequences. Its translated aa sequence had a 71 aa N-terminal truncation and a C-terminal 76 aa proline-rich extension. Expression of the six Tn-C sequences across a range of tissue types in lobster will use end-point RT-PCR. Fiber-type-specific expression will be quantified by real-time PCR. Further work will determine the relationship between Tn-C isoform expression patterns and: muscle functional properties; molt cycle; and expression of myostatin, which is thought to inhibit muscle growth prior to molting. Supported by NSF (IBN-0618203).