The occurrence of two types of fast skeletal myosin heavy chains from abdominal muscle of kuruma shrimp Marsupenaeus japonicus and their different tissue distribution

Abstract

SUMMARYShrimps belong to the class Crustacea, which forms a large, diverse group in the invertebrates. However, the physiology and biochemistry of their skeletal muscles have been poorly understood compared with those from vertebrates including mammals and fish. The present study focused on myosin, the major protein in skeletal muscle, from adult specimens of kuruma shrimp Marsupenaeus japonicus. Two types of the gene encoding myosin heavy chain (MHC), a large subunit of the myosin molecule, were cloned from abdominal fast skeletal muscle and defined as MHCa and MHCb. Protein analysis revealed that the MHCa isoform was expressed at a higher level than the MHCb isoform. The full-length cDNA clones of MHCa and MHCb consisted of 5929bp and 5955bp, respectively, which encoded 1912 and 1910 amino acids, respectively. Both were classified into fast muscle type by comparison with the partially deduced amino acid sequences of fast-type and slow-type (S 1 , slow twitch) MHCs reported previously for the American lobster Homarus americanus. The amino acid identities between MHCa and MHCb of kuruma shrimp were 78%, 60% and 72% in the regions of subfragment-1, subfragment-2 and light meromyosin, respectively, and 71% in total. In situ hybridisation using anti-sense RNA-specific probes, along with northern blot analysis using different tissues from abdominal muscle, revealed the different localisation of MHCa and MHCb transcripts in abdominal fast skeletal muscle, suggesting their distinct physiological functions.

Shared Gene Structures and Clusters of Mutually Exclusive Spliced Exons within the Metazoan Muscle Myosin Heavy Chain Genes

“…This implies that the last common ancestor of the copepods must have developed an MXE-less muscle myosin heavy chain gene followed by extensive gene duplications. Multiple Mhc genes have experimentally been found in shrimps [37]–[39] and gammarid amphipods [40] and some could be obtained in full-length (Figure 1). These group closer to the Lepeophtheirus Mhc genes than to the Daphnia Mhc1 implying that encoding of multiple, but not alternatively spliced Mhc genes is a common characteristic of many crustaceans.…”

Cloning of Skeletal Myosin Heavy Chain Gene Family From Adult Pleopod Muscle and Whole Larvae of Shrimps

“…CODEHOP (COnsensus‐DEgenerate Hybrid Oligonucleotide Primers) (Rose et al, ) was used to design degenerate primer F (Table ) based on the deduced amino acid sequences of MHC from fruit fly Drosophila melanogaster (DDBJ/EMBL/GenBank accession number AAA28686) and American lobster fast‐ (U03091) and S 1 slow twitch‐type (AY232598) MHCs. This primer has been demonstrated to amplify DNA fragments encoding MHCs from abdominal muscle of kuruma, black tiger, and Pacific white shrimps as reported previously (Koyama et al, ).…”

“…To shed light on crustacean skeletal muscle as a comparative model with vertebrate and other invertebrate counterparts, it is useful to investigate primary structures, expression patterns, and tissue distributions of MHCs in shrimps. We reported previously the complete sequences of two MHC genes ( MHC s), MHCa and MHCb , from abdominal muscles of adult specimens of kuruma Marsupenaeus japonicus , black tiger Penaeus monodon and Pacific white Penaeus vannnamei shrimps (Koyama et al, ). MHCa transcripts were localized in flexor muscle, whereas MHCb transcripts were in extensor and flexor muscles.…”

Arms of larval seastars of Pisaster ochraceus provide versatility in muscular and ciliary swimming

“…A larva has the challenges of changing its direction of swimming when it encounters objects and of maintaining its direction of swimming when shear turns its body [19,26–28]. The ability of a brachiolaria to move its arms to turn or rotate may help it counter the effects of shear.…”

“…The ability of a brachiolaria to move its arms to turn or rotate may help it counter the effects of shear. Swimming of different asteroid larvae in shear and turbulence can be compared in the laboratory, as has been done with larvae of echinoids and mollusks [19,26,29–33]. Such observations will demonstrate the extent to which an evolutionary innovation in larval arms has enhanced performance in swimming.…”