Sheep heart RNA stimulates myofibril formation and beating in cardiac mutant axolotl hearts in organ culture.
In the Mexican axolotl, Ambystoma mexicanum, recessive mutant gene c, when homozygous, results in a failure of the heart to form sarcomeric myofibrils and contract normally. Previous studies have shown that purified RNA from normal anterior endoderm or from medium conditioned with anterior endoderm/pre-cardiac mesoderm has the capacity to rescue mutant hearts in organ culture. In the present study, RNA extracted from adult sheep heart was tested for its capacity to promote differentiation in the mutant axolotl hearts. Mutant hearts cultured in the presence of the sheep heart RNA in Steinberg's solution for 48 h displayed rhythmic contractions. Ultrastructural studies showed that the rescued mutant axolotl ventricular myocardial cells contained myofibrils of normal morphology. Mutant hearts cultured in Steinberg's solution alone did not beat throughout their lengths and myofibrils were not observable in the ventricles. Confocal microscopy confirmed the increase of Tropomyosin expression and formation of myofibrils in mutant hearts treated by sheep heart RNA. Thus, sheep heart RNA promotes myofibrillogenesis and the development of contractile function in embryonic cardiac mutant axolotl hearts.
Zhang
Chi
C
Department of Biomedical Sciences, Florida Atlantic University, 777 Glades Road, Boca Raton, FL 33431, USA.
LaFrance
Sherrie M
SM
Lemanski
Sharon L
SL
Huang
Xupei
X
Dube
Dipak K
DK
Lemanski
Larry F
LF
D000558:Ambystoma mexicanum / Q000196:embryology* / Q000502:physiology; D000818:Animals; D002454:Cell Differentiation; D003470:Culture Media; D047108:Embryonic Development; D005260:Female; D006321:Heart / Q000196:embryology* / Q000502:physiology; D008297:Male; D018613:Microscopy, Confocal; D024510:Muscle Development / Q000502:physiology*; D009200:Myocardial Contraction / Q000502:physiology*; D009210:Myofibrils; D009924:Organ Culture Techniques; D012313:RNA; D012756:Sheep
D003470:Culture Media; D012313:RNA