Summary
Recessive mutant genec in axolotls results in a failure of embryonic heart function. Earlier morphological studies showed that the mutant myocardial cells lack organized sarcomeric myofibrils. Electrophoresis and immunofluorescent studies suggested that the mutant heart cells contain substantial amounts of actin, myosin and α-actinin; however, tropomyosin appeared deficient. In the present study, we employed a newly developed extremely sensitive solid-phase radioimmunoassay method to quantitate very accurately the tropomyosin levels in normal and mutant sibling hearts at early (stage 35), intermediate (stage 39) and late (stage 41) developmental stages. Our results demonstrate that cardiac mutant hearts contain significantly lower than normal quantities of antigenically detectable tropomyosin at all of the developmental stages examined. This insufficiency of tropomyosin in mutant hearts may be a primary cause at the cell level for their failure to form organized myofibrils.
Similar content being viewed by others
References
GERGELY, J. (1976) Troponin-tropomyosin dependent regulation of muscle contraction by calcium. InCell Motility. Cold Spring Habor Conferences on Cell Proliferation (edited by GOLDMAN, R., POLLARD, T. and ROSENBAUM, J.), pp. 137–149. New York: Cold Spring Habor Laboratories.
HILL, C. S. & LEMANSKI, L. F. (1969) Morphological studies on cardiac lethal mutant salamander hearts in organ cultures.J. exp. Zool. 209, 1–20.
HUMPHERY, R. R. (1972) Genetic and experimental studies on a mutant gene (c) determining absence of heart action in embryos of the Mexican axolotl (Ambystoma mexicanum).Devl Biol. 27, 365–75.
JACOBSON, A. G. & DUNCAN, J. T. (1968) Heart induction in salamanders.J. exp. Zool. 167, 79–103.
LEMANSKI, L. F. (1973a) Heart development in the Mexican salamander,Ambystoma mexicanum. II. Ultrastructure.Am. J. Anat. 136, 487–525.
LEMANSKI, L. F. (1973b) Morphology of developing heart in cardiac lethal mutant Mexican axolotls,Ambystoma mexicanum.Devl Biol. 33, 312–33.
LEMANSKI, L. F. (1976) Morphological and biochemical abnormalities in hearts of cardiac mutant salamanders (Ambystoma mexicanum).Supramolec. Struct. 5, 221–38.
LEMANSKI, L. F. (1979) Role of tropomyosin in actin filament formation in embryonic salamander heart cells.J. Cell Biol. 82, 227–38.
LEMANSKI, L. F., FULDNER, R. A. & PAULSON, D. J. (1980) Immunofluorescence studies for myosin, α-actinin and cardiac lethal mutant Mexican axolotls,Ambystoma mexicanum.J. Embryol. exp. Morph. 55, 1–15.
LEMANSKI, L. F., MOOSEKER, M. S., PEACHEY, L. D. & IYENGAR, M. R. (1976) Studies of muscle proteins in embryonic myocardial cells of cardiac lethal mutant Mexican axolotls. (Ambystoma mexicanum) by use of heavy meromyosin binding and sodium dodecyl sulfate polyacrylamide gel electrophoresis.J. Cell Biol. 68, 375–88.
LEMANSKI, L. F., PAULSON, D. J. & HILL, C. S. (1979) Normal anterior endoderm corrects the heart defect in cardiac mutant salamanders (Ambystoma mexicanum).Science 204, 860–2.
LOWRY, D. H., ROSEBROUGH, N. H., FARR, A. L. & RANDALL, R. J. (1951) Protein measurement with the Folin phenol reagent.J. biol. Chem. 193, 265–75.
MOORE, P. B. & LEMANSKI, L. F. (1982) A radioimmunoassay method for quantitation of tropomyosin in heart homogenates.J. Musc. Res. Cell Motility 3, 145–60.
RUGH, R. (1962)Experimental Embryology. p. 15. Minneapolis: Burgess Publishing Company.
SCHRECKENBERG, G. M. & JACOBSON, A. G. (1975) Normal stages of development of the axolotl,Ambystoma mexicanum.Devl Biol. 42, 391–408.
WOODROOFE, M. N. & LEMANSKI, L. F. (1981) Actin in cardiac mutant and normal axolotl hearts.J. Cell Biol. 87, 266a.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Moore, P.B., Lemanski, L.F. Quantification of tropomyosin by radioimmunoassay in developing hearts of cardiac mutant axolotls,Ambystoma mexicanum . J Muscle Res Cell Motil 3, 161–167 (1982). https://doi.org/10.1007/BF00711940
Received:
Revised:
Issue Date:
DOI: https://doi.org/10.1007/BF00711940