Cyclins A, B, D3, and E are down-regulated during ATRA-induced differentiation of U-937 cells.

(A) Cells were induced by ATRA and harvested at the indicated times, and total mRNA was prepared. The regulation of cyclin mRNA during ATRA treatment was analyzed by RPA using the hCYC-1 multiprobe template. (B) The protein levels of cyclins A, B, D2, D3, and E during ATRA-induced differentiation were determined by Western blot analysis using whole cell lysates.