Lysine deficiency reduces transcription activity and concentration of chromatin proteins reversibly in rat liver

The reversible effect of dietary lysine deficiency was studied in young adult rats. During 6 days on a lysine diet the rats maintained the same body weight. During 2 days of recovery body weight gain was that of the controls. Liver nuclei were isolated, incubated with micrococcus nuclease and chromatin fractionated in to a 2 000 X g pellet, 102 000 X g pellet and supernatant fraction. Chromatin-bound RNA polymerase 1 plus III activity decreased by 15% per mg of fractional and nuclear DNA and by 30% per total liver. The corresponding decrease of RNA polymerase II activity was 30% and 40%. Recovery from lysine deficiency was complete after 2 days of refeeding the amino acid. Chromatin proteins of the 102 000 X g pellet were characterized by polyacrylamide gel electrophoresis in sodium dodecylsulfate and by 2-dimensional gel electrophoresis. Quantitative but no qualitative differences between the proteins of the dietary groups were observed. Relative to DNA the non-histone proteins decreased in the lysine deficient group by 43% and histones by 10%. It is concluded that RNA synthesis is restored to its original level within 2 days of refeeding lysine after 6 days of lysine deficiency.