Isolation of transcriptionally active nuclei from striated muscle using Percoll density gradients

A procedure is described utilizing Percoll density media for the separation of nuclei and myofibrils in homogenates of adult skeletal muscle. Using this method, transcriptionally active nuclei can be readily obtained in relatively high yield (approximately 30%). In vitro RNA polymerase run-on-labeled RNAs isolated from these nuclei can be used in hybridization assays to study the transcriptional activities of specific genes. Percoll density gradient centrifugation should be useful for the isolation of nuclei from a variety of other tissues in which, like skeletal muscle, subcellular or tissue components cosediment with nuclei in conventional sucrose density centrifugation.