Journal of Muscle Research and Cell Motility

, Volume 36, Issue 4–5, pp 339–347 | Cite as

Nucleotide and protein sequences for dog masticatory tropomyosin identify a novel Tpm4 gene product

  • Elizabeth A. Brundage
  • Brandon J. Biesiadecki
  • Peter J. Reiser
Original Paper


Jaw-closing muscles of several vertebrate species, including members of Carnivora, express a unique, “masticatory”, isoform of myosin heavy chain, along with isoforms of other myofibrillar proteins that are not expressed in most other muscles. It is generally believed that the complement of myofibrillar isoforms in these muscles serves high force generation for capturing live prey, breaking down tough plant material and defensive biting. A unique isoform of tropomyosin (Tpm) was reported to be expressed in cat jaw-closing muscle, based upon two-dimensional gel mobility, peptide mapping, and immunohistochemistry. The objective of this study was to obtain protein and gene sequence information for this unique Tpm isoform. Samples of masseter (a jaw-closing muscle), tibialis (predominantly fast-twitch fibers), and the deep lateral gastrocnemius (predominantly slow-twitch fibers) were obtained from adult dogs. Expressed Tpm isoforms were cloned and sequencing yielded cDNAs that were identical to genomic predicted striated muscle Tpm1.1St(a,b,b,a) (historically referred to as αTpm), Tpm2.2St(a,b,b,a) (βTpm) and Tpm3.12St(a,b,b,a) (γTpm) isoforms (nomenclature reflects predominant tissue expression (“St”—striated muscle) and exon splicing pattern), as well as a novel 284 amino acid isoform observed in jaw-closing muscle that is identical to a genomic predicted product of the Tpm4 gene (δTpm) family. The novel isoform is designated as Tpm4.3St(a,b,b,a). The myofibrillar Tpm isoform expressed in dog masseter exhibits a unique electrophoretic mobility on gels containing 6 M urea, compared to other skeletal Tpm isoforms. To validate that the cloned Tpm4.3 isoform is the Tpm expressed in dog masseter, E. coli-expressed Tpm4.3 was electrophoresed in the presence of urea. Results demonstrate that Tpm4.3 has identical electrophoretic mobility to the unique dog masseter Tpm isoform and is of different mobility from that of muscle Tpm1.1, Tpm2.2 and Tpm3.12 isoforms. We conclude that the unique Tpm isoform in dog masseter is a product of the Tpm4 gene and that the 284 amino acid protein product of this gene represents a novel myofibrillar Tpm isoform never before observed to be expressed in striated muscle.


Tropomyosin Masseter Dog Jaw-adductor Myosin Masticatory 



The authors thank Dr. Sarah Hitchcock-DeGregori for very valuable consultation during the course of this study. The authors also thank Dr. Sabahattin Bicer for assistance with muscle sample collection. Support for this work was obtained from NIH Grant HL114940 (to B.J.B.).


  1. Bergrin M, Bicer S, Lucas CA, Reiser PJ (2006) Three-dimensional compartmentalization of myosin heavy chain and light chain isoforms within dog thyroarytenoid muscle. Am J Physiol Cell Physiol 290:C1446–C1458CrossRefPubMedGoogle Scholar
  2. Bicer S, Reiser PJ (2004) Myosin light chain isoform expression among single mammalian skeletal muscle fibers: species variations. J Muscle Res Cell Motil 25:623–633CrossRefPubMedGoogle Scholar
  3. Bicer S, Reiser PJ (2013) Complex tropomyosin and troponin T isoform expression patterns in orbital and global fibers of adult dog and rat extraocular muscles. J Muscle Res Cell Motil 34:211–231CrossRefPubMedGoogle Scholar
  4. Bicer S, Patel RJ, Williams JB, Reiser PJ (2011) Patterns of tropomyosin and troponin-T isoform expression in jaw-closing muscles of mammals and reptiles that express masticatory myosin. J Exp Biol 214:1077–1085CrossRefPubMedGoogle Scholar
  5. Biesiadecki BJ, Elder BD, Yu ZB, Jin JP (2002) Cardiac troponin T variants produced by aberrant splicing of multiple exons in animals with high instances of dilated cardiomyopathy. J Biol Chem 277:50275–50285CrossRefPubMedGoogle Scholar
  6. Blough ER, Rennie ER, Zhang F, Reiser PJ (1996) Enhanced electrophoretic separation and resolution of myosin heavy chains in avian and mammalian skeletal muscles. Anal Biochem 233:31–35CrossRefPubMedGoogle Scholar
  7. Desjardins PR, Burkman JM, Shrager JB, Allmond LA, Stedman HH (2002) Evolutionary implications of three novel members of the human sarcomeric myosin heavy chain gene family. Mol Biol Evol 19:375–393CrossRefPubMedGoogle Scholar
  8. Geeves MA, Hitchcock-DeGregori SE, Gunning PW (2015) A systematic nomenclature for mammalian tropomyosin isoforms. J Muscle Res Cell Motil 36:147–153PubMedCentralCrossRefPubMedGoogle Scholar
  9. Gunning PW, Schevzov G, Kee AJ, Hardeman EC (2005) Tropomyosin isoforms: divining rods for actin cytoskeleton function. Trends Cell Biol 15:333–341CrossRefPubMedGoogle Scholar
  10. Gunning P, O’Neill G, Hardeman E (2008) Tropomyosin-based regulation of the actin cytoskeleton in time and space. Physiol Rev 88:1–35CrossRefPubMedGoogle Scholar
  11. Hardy S, Theze N, Lepetit D, Allo MR, Thiebaud R (1995) The Xenopus laevis TM-4 gene encodes non-muscle and cardiac tropomyosin isoforms through alternative splicing. Gene 156:265–270CrossRefPubMedGoogle Scholar
  12. Heeley DH, Dhoot GK, Frearson N, Perry SV, Vrbova G (1983) The effect of cross-innervation on the tropomyosin composition of rabbit skeletal muscle. FEBS Lett 152:282–286CrossRefPubMedGoogle Scholar
  13. Heeley DH, Dhoott GK, Perry SV (1985) Factors determining the subunit composition of tropomyosin in mammalian skeletal muscle. Biochem J 226:461–468PubMedCentralCrossRefPubMedGoogle Scholar
  14. Hitchcock-DeGregori SE, Song Y, Moraczewska J (2001) Importance of internal regions and the overall length of tropomyosin for actin binding and regulatory function. Biochemistry 40:2104–2112CrossRefPubMedGoogle Scholar
  15. Hitchcock-DeGregori SE, Song Y, Greenfield NJ (2002) Functions of tropomyosin’s periodic repeats. Biochemistry 41:15036–15044CrossRefPubMedGoogle Scholar
  16. Hoh JFY (2002) ‘Superfast’ or masticatory myosin and the evolution of jaw-closing muscles of vertebrates. J Exp Biol 205:2203–2210PubMedGoogle Scholar
  17. Hoh JFY, Kang LHD, Sieber LG, Lim JHY, Zhong WWH (2006) Myosin isoforms and fibre types in jaw-closing muscles of Australian marsupials. J Comp Physiol B 176:685–695CrossRefPubMedGoogle Scholar
  18. Kang LH, Rughani A, Walker ML, Bestak R, Hoh JF (2010) Expression of masticatory-specific isoforms of myosin heavy-chain, myosin-binding protein-C and tropomyosin in muscle fibers and satellite cell cultures of cat masticatory muscle. J Histochem Cytochem 58:623–634PubMedCentralCrossRefPubMedGoogle Scholar
  19. Kato C, Saeki Y, Yanagisawa K (1985) Ca2+ sensitivities and transient tension responses to step-length stretches in feline mechanically stripped single-fibre jaw-muscle preparations. Arch Oral Biol 30:429–432CrossRefPubMedGoogle Scholar
  20. Perry SV (2001) Mammalian tropomyosin: distribution, properties and function. J Muscle Res Cell Motil 22:5–49CrossRefPubMedGoogle Scholar
  21. Qin H, Morris BJ, Hoh JFY (1994) Isolation and structure of cat superfast myosin light chain-2 cDNA and evidence for the identity of its human homologue. Biochem Biophys Res Comm 200:1277–1282CrossRefPubMedGoogle Scholar
  22. Qin H, Hsu MK, Morris BJ, Hoh JF (2002) A distinct subclass of mammalian striated myosins: structure and molecular evolution of “superfast” or masticatory myosin heavy chain. J Mol Evol 55:544–552CrossRefPubMedGoogle Scholar
  23. Reiser PJ, Bicer S (2007) High force generation and moderate shortening velocity in jaw-closing muscle fibers expressing masticatory (‘superfast’) myosin. Biophys J Suppl S 191AGoogle Scholar
  24. Reiser PJ, Bicer S, Chen Q, Zhu L, Quan N (2009) Masticatory (‘Superfast’) myosin heavy chain and embryonic/atrial myosin light chain 1 in rodent jaw-closing muscles. J Exp Biol 212:2511–2519CrossRefPubMedGoogle Scholar
  25. Reiser PJ, Bicer S, Patel R, An Y, Chen Q, Quan N (2010) The myosin light chain 1 isoform associated with masticatory myosin heavy chain in mammals and reptiles is embryonic/atrial MLC1. J Exp Biol 213:1633–1642CrossRefPubMedGoogle Scholar
  26. Rowlerson A, Pope B, Murray J, Whalen RG, Weeds AG (1981) A novel myosin present in cat jaw-closing muscles. J Muscle Res Cell Motil 2:415–428CrossRefGoogle Scholar
  27. Rowlerson A, Heizmann CW, Jenny E (1983a) Type-specific proteins of single IIM fibres from cat muscle. Biochem Biophys Res Commun 113:519–525CrossRefPubMedGoogle Scholar
  28. Rowlerson A, Mascarello F, Veggetti A, Carpene E (1983b) The fibre-type composition of the first branchial arch muscles in Carnivora and Primates. J Muscle Res Cell Motil 4:443–472CrossRefPubMedGoogle Scholar
  29. Schevzov G, Whittaker SP, Fath T, Lin JC, Gunning PW (2011) Tropomyosin isoforms and reagents. BioArchitecture 1:135–164PubMedCentralCrossRefPubMedGoogle Scholar
  30. Sender PM (1971) Muscle fibrils: solubilization and gel electrophoresis. FEBS Lett 17:106–110CrossRefPubMedGoogle Scholar
  31. Singh A, Hitchcock-DeGregori SE (2006) Dual requirement for flexibility and specificity for binding of the coiled-coil tropomyosin to its target, actin. Structure 14:43–50CrossRefPubMedGoogle Scholar
  32. Spinner BJ, Zajdel RW, McLean MD, Denz CR, Dube S, Mehta S, Choudhury A, Nakatsugawa M, Dobbins N, Lemanski LF, Dube DK (2002) Characterization of a TM-4 type tropomyosin that is essential for myofibrillogenesis and contractile activity in embryonic hearts of the Mexican axolotl. J Cell Biochem 85:747–761CrossRefPubMedGoogle Scholar
  33. Toniolo L, Cancellara P, Maccatrozzo L, Patruno M, Mascarello F, Reggiani C (2008) Masticatory myosin unveiled: first determination of contractile parameters of muscle fibers from carnivore jaw muscles. Am J Physiol Cell Physiol 295:C1535–C1542CrossRefPubMedGoogle Scholar
  34. Wolska BM, Wieczorek DF (2003) The role of tropomyosin in the regulation of myocardial contraction and relaxation. Pflugers Arch 446:1–8CrossRefPubMedGoogle Scholar

Copyright information

© Springer International Publishing Switzerland 2015

Authors and Affiliations

  • Elizabeth A. Brundage
    • 1
  • Brandon J. Biesiadecki
    • 1
  • Peter J. Reiser
    • 2
  1. 1.Department of Physiology and Cell Biology, College of MedicineThe Ohio State UniversityColumbusUSA
  2. 2.Division of Biosciences, College of DentistryThe Ohio State UniversityColumbusUSA

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