Effect of Per1, Cry2, and Clock on circadian gene expression in mpkCCDc14 and AML12 cells. mpkCCDc14 or AML12 cells were treated with nontarget, Per1, Cry2, or Clock siRNA or a combination of both Per1 and Cry2 or Cry2 and Clock for 48 h. A–C: QPCR was used to evaluate changes in Per1 (A and B), Clock (C and D), Cry2 (E and F) gene expression in mpkCCDc14 and AML12 siRNA treated cells vs. nontarget. P < 0.05, **P < 0.01; n = 3. Values are means ± SE.