Regulation of ribosomal DNA transcription during neonatal cardiomyocyte hypertrophy.

In summary, the increased capacity for protein synthesis that is a constant feature in all forms of cardiac hypertrophy is largely mediated by accelerated ribosome biogenesis. Experiments with neonatal cardiomyocytes in culture indicate that the activity of the rDNA transcription factor, UBF, may contribute to the regulation of rDNA transcription during the hypertrophic growth process. The observations of parallel responses in three different models of neonatal cardiomyocyte hypertrophy suggest that further studies on the regulation of UBF should lead to a clearer understanding of the pathways that lead to hypertrophy. Possible alterations in the activities and/or amounts of other factors associated with rDNA transcription including SL-1, TFIC and the polymerase I enzyme itself, may also contribute to the regulation of cardiomyocyte growth; however, this remains to be demonstrated.