Figure 4.

RT–PCR analysis. (A) The DHFR gene structure is diagramed. Black boxes indicate exons. Primer sets used for PCR are shown. (B) Poly(A)⁺ RNA from control mock-transfected (lane 1) or from siRNA-408 and siRNA-613 transfected CFIm25 knocked-down (lanes 2 and 3) HeLa cells were reverse transcribed using an oligo-dT primer, and then DHFR cDNA fragments were amplified by PCR. A 100 bp DNA ladder was loaded in lane M.