Transfection of isoform-specific sense and anti-sense oligonucleotides in the ventricle of normal hearts. a. Confocal microscopy of normal axolotl hearts transfected with TPM1a anti-sense oligonucleoted and subsequently stained with CH1 monoclonal antibody. TPM1a anti-sense oligonucleotide did not result in a drastic disruption of organized myofibrils in the ventricle, which is comparable with the normal untreated control hearts (figure not shown). Sarcomeric TM can be seen in most of the cells. Contractility of the anti-sense treated hearts were not affected. b. TPM1κ anti-sense transfection disrupted the myofibril organization in normal axolotl heart compared to TPM1κ sense transfection. Very little organized structure is seen when examined by the tropomyosin staining. The secondary antibody is contained within amorphous areas in the cells. c. It shows that the TPM1κ sense oligonucleoides did not affect the structure. Since no effect on myofibril structure with TPM1κ sense was observed, we tagged the oligonucleotide with FITC (green) to verify its presence and found it to be within the myocytes. Double staining of the nucleus (green) and the myofibrils at the periphery of the cells (red) can be seen. The green staining is ovoid in shape and primarily located at the center of the cells . Confocal z-series images of stage ~38 embryonic axolotl hearts transfected with either TPM1κ anti-sense or sense oligonucleotides. Immunodetection of sarcomeric tropomyosin using CH1 monoclonal antibody is shown in red. The results depicted by this figure suggests that TPM1κ plays a critical role in maintaining the myofibrillar structure in embryonic axolotl hearts.