A chromEM-staining protocol optimized for cardiac tissue

Three-dimensional (3D) chromatin organization has a key role in defining the transcription program of cells during development. Its alteration is cause gene expression changes responsible for several diseases. Thus, we need new tools to study this aspect regulation. To end, ChromEM was recently developed: an electron-microscopy staining technique that selectively marks nuclear DNA without altering its structure and, thus, allows better visualization 3D conformation. However, despite increasingly frequent application on cells, it not yet been applied visualize ultrastructure tissues. Here, provide protocol carry out myocardial tissue harvested from left ventricles C57BL/6J mice and use combination with transmission electron microscopy (TEM) measure some morphological parameters peripheral heterochromatin cardiomyocytes. This could also be used, tomography, cardiomyocytes different aspects heart pathobiology (e.g., development, cardiac aging, failure) as well help set-up other