Expression of the MUC1 isoform specific mRNA in mouse DA3 cells transfected with plasmids pDpr, pDprΔ2154, pDprΔ2446, pDprΔ2839 and ppolyIII. DA3 cells were transfected with plasmid DNA. Cells transfected with ppolyIII were used as negative controls. DA3 cells stably transfected with MUC1/SEC, MUC1/TM and MUC1/Y cDNA were used as positive control. Total RNA was extracted 48 hrs after transfection and cDNA was synthesized. PCR amplification of MUC1 isoform specific fragments were performed using isoform specific primers. PCR products were separated by electrophoresis on 1.2% agarose gel and stained with ethidium bromide. A – Schematic structure of the pDpr, pDprΔ2154, pDprΔ2446, pDprΔ2839 plasmids and the table of the MUC1/SEC, MUC1/TM and MUC1/Y mRNA expression in transfected DA3 cells. B – RT-PCR of the MUC1 isoform specific RNA extracted from DA3 cells transiently transfected with indicated plasmids. Lane M-DNA marker; lanes 1, 4, 7, 10 and 13 (negative control) – PCR performed with MUC1/SEC specific primers; lanes 2, 5, 8, 11 and 14 (negative control) – PCR performed with MUC1/TM specific primers; lanes 3, 6, 9, 12 and 15 (negative control) – PCR performed with MUC1/Y specific primers. Positive control: DA3 cells stably transfected with MUC1 isoform specific cDNA. Lane SEC – cells expressed MUC1/SEC; lane TM – cells expressed MUC1/TM and lane Y – cells expressed MUC1/Y RNAs.