Figure 4.

Knockdown of STRA6 significantly decreases HSD17B2, a gene known to be induced by RA. STRA6 is the main retinol receptor in cells and controls retinol uptake. Results represent the mean ± sem for six independent experiments using tissues from different subjects. *, P < 0.05. A, STRA6 knockdown in ESC. B, HSD17B2 gene expression decreases when STRA6 is knocked down. Because there is less retinol uptake in cells, less RA is available to induce HSD17B2. C, Knockdown of STRA6 markedly decreased ³H-retinol/RBP uptake in normal ESC. Radioactivity was measured with a scintillation counter. siCTL, Nontargeting negative control siRNA; siSTRA6, siRNA against STRA6.