Transcription of the non-repetitive genome in liver hypertrophy and the homology between nuclear RNA of normal and 12 H-regenerating liver.

The percentage of the non-repetitive genome transcribed and the complexity of nuclear RNA were estimated in normal and 12 h-regenerating rat liver. Nuclear RNA from normal or 12 h-regenerating liver hybridizes with approximately 6.1% of non-repetitive DNA (12.2% of the single-copy genome, assuming assymetric transcription). The estimated complexity of either of these nuclear RNA populations is 7.6 . 10(10) daltons, which is approximately 7 times higher than that calculated for polysomal mRNA. Cross hybridization experiments did not show differences between the nuclear RNA populations of normal and 12 h-regenerating liver. The results indicate that liver hypertropy (without hyperplasia) may be brought about without a large increase in the proportion of the non-repetitive genome transcribed.