Figure 5.

Cyclin D1 promotes purine synthesis. Hepatocytes were cultured as in Figure 3. A, abundance of ¹³C labeled adenine in AXP (AMP, ADP, and ATP combined) by NMR. B, ¹³C-labeled isotopologues of ATP by IC-UHR FTMS. C, abundance of ¹³C-enriched purine rings of ATP, GFP, and IMP, calculated by the sum of the ¹³C M6–M8 isotopologues. D, changes in the level of mRNA transcripts of genes involved in purine synthesis induced by cyclin D1 siRNA (relative to control siRNA) from our prior RNA-seq study in AML12 hepatocytes cultured under these conditions (ref. (14)). E, Western blot of ATF4 and Psat1. Relative expression is shown in the graphs below. F, expression of Mthfd2, Ppat, and Psat1 proteins by reverse phase protein array analysis. IC-UHR FTMS, ion chromatography coupled with ultra high-resolution Fourier transform mass spectrometry.