Changes in p21WAF1/CIP1 and p53 in CerS2 null mouse liver. A, Western blot showing changes in p21WAF1/CIP1 levels. The values show the fold difference in p21WAF1/CIP1 levels in WT (+/+) versus CerS2 null mice (−/−), normalized to glyceraldehyde-3-phosphate dehydrogenase (GAPDH). The two right-hand lanes show that there is no change in p21WAF1/CIP1 levels in kidney. B, quantitative PCR analyses showing transcriptional up-regulation of p21WAF1/CIP1 and p53 in CerS2 null mouse liver relative to WT littermate controls, and normalized to glyceraldehyde-3-phosphate dehydrogenase. n = 2–6; *, p < 0.05; **, p < 0.01.