Figure 3.

Synthesis of transcripts beyond the SL-region strongly correlates with the estrogen mediated stimulation or drug mediated down-regulation of endogenous MYB gene. Diagrammatic representation of human MYB (A) and cyclophilin A (B) genes. In the case of MYB, the position of the SL and poly dT sites are shown. Positions of intron based primers are indicated as Pre-I, Post-III and Post-IV. Full-length MYB transcripts are detected by MYB exon primer recognizes the sequence of exon8/9 region. Cyclophilin A full-length transcripts are detected by Cyclo Exon primers which recognize exon 5. (C) Ligand bound ERα relieves transcriptional attenuation of MYB gene expression. MCF-7 cells were kept 48 h in DMEM medium supplemented with CSS and incubated 2 h with 10 nM estrogen. The difference in gene expression in the presence of estrogen is shown as a fold change in comparison to the non-estrogen-treated cells. (D) DRB-mediated down-regulation of MYB transcription is associated with significant reduction in the synthesis of transcripts beyond the SL-dT region. MCF-7 cells were treated with 25 µM DRB for 4 h and synthesis of transcripts was estimated by qRT-PCR. Gene expression in the presence of drug was compared with the untreated control cells.