Characterization of Basal and Estrogen-Regulated Antisense Transcription in Breast Cancer Cells: Role in Regulating Sense Transcription

We have mined genomic data to define three classes of antisense transcription in MCF-7 cells based on where their antisense transcription termination sites reside relative to their cognate sense mRNA and lncRNA genes. These three classes differ in their response to estrogen treatment, the enrichment of a number of genomic features associated with active promoters (H3K4me3, RNA polymerase II, open chromatin architecture), and the biological functions of their cognate sense genes as analyzed by DAVID gene ontology. We further characterized two estrogen-regulated antisense transcripts arising from the MYC gene in MCF-7 cells, showing that these antisense transcripts are five-prime capped, three-prime polyadenylated, and localized to different compartments of the cell. MCF-7 cells treated with ethanol (vehicle) or 17beta-estradiol (E2; 100 nM).