Molecular Characterization of Tropomyosin and Its Potential Involvement in Muscle Contraction in Pacific Abalone

Tropomyosin (TPM) is a contractile protein responsible for muscle contraction through its actin-binding activity. The complete sequence of in () was 2160 bp, encoding 284 amino acids, and contained a TPM signature motif and a TPM domain. Gene ontology (GO) analysis based on the amino acid sequence predicted Hdh-TPM to have an actin-binding function in the cytoskeleton. The 3D analysis predicted the Hdh-TPM to have a coiled-coil α-helical structure. Phylogenetically, Hdh-TPM formed a cluster with other TPM/TPM1 proteins during analysis. The tissue-specific mRNA expression analysis found the higher expression of in the heart and muscles; however, during embryonic and larval development (ELD), the higher expression was found in the trochophore larvae and veliger larvae. expression was upregulated in fast-growing abalone. Increasing thermal stress over a long period decreased expression. Long-term starvation (>1 week) reduced the mRNA expression of in muscle; however, the mRNA expression of was significantly higher in the mantle, which may indicate overexpression. This study is the first comprehensive study to characterize the gene in Pacific abalone and to report the expression of in different organs, and during ELD, different growth patterns, thermal stress, seasonal changes, and starvation.