THE CARDIAC MUTANT-GENE-C IN AXOLOTLS - CELLULAR, DEVELOPMENTAL, AND MOLECULAR STUDIES

The cardiac mutant axolotl is an interesting model for studying heart development. The mutant gene results in a failure of heart cells to fo rm organized myofibrils and as a consequence the heart fails to beat. Experiments have shown that mutant hearts can be ''rescued'' (i.e., tu rned into normally contracting organs) by the addition of RNA purified from conditioned media produced by normal embryonic anterior endoderm -mesoderm cultures. These corrected hearts form myofibrils of normal m orphology. New advances in recombinant DNA technology applied to this system should provide significant insights into the regulatory mechani sms of myofibrillogenesis as well as the inductive processes related t o the control of gene expression during embryonic heart development. I n a broader biological sense, the use of gene c in axolotls is potenti ally capable of helping to solve major unanswered questions in modern biology related to the genetic regulation of differentiation in verteb rates.