Alternative splicing of the first intron of the steroid receptor RNA activator (SRA) participates in the generation of coding and noncoding RNA isoforms in breast cancer cell lines.

The Steroid Receptor RNA Activator 1 (SRA1) has originally been described as a noncoding RNA specifically activating steroid receptor transcriptional activity. We have, however, identified, in human breast tissue, exon- 1 extended SRA1 isoforms containing two initiating AUG codons and encoding a protein we called SRAP. We recently reported a decreased estrogen receptor activity in breast cancer cells overexpressing SRAP, suggesting antagonist roles played by SRA1 RNA and SRAP.