Activation of myosin heavy chain genes during cardiac hypertrophy.

Nick translation of intact rat heart nuclei has shown that the incorporation of [3H]–dATP is greater in hypertrophic heart nuclei than in normal heart nuclei suggesting that hypertrophic heart nuclei have more DNase I sensitive regions than normal heart nuclei. DNase I sensitivity analysis has shown that the rate and extent of digestion of myosin heavy chain genes are greater in hypertrophic than in normal heart nuclei. Dot blot hybridization analysis of myosin heavy chain transcripts from hypertrophic heart nuclei using myosin heavy chain cDNA as probe has shown that the sensitivity of myosin heavy chain genes to DNase I in hypertrophic heart nuclei correlates with myosin heavy chain gene activation and increased number of transcripts.