Steroid receptor RNA activator 1 (SRA), with 237-amino acid protein (about 27kDa), belongs to the growing family of functional non-coding RNAs. SRA was originally described as the first functional noncoding RNA able to specifically coactivate the activity of steroid receptors. Specifically, SRA exists as both an RNA transcript that forms a complex with steroid receptor coactivator-1 and as a stably expressed protein. Its expression is strongly up-regulated in many human tumors of the breast, uterus, and ovary, suggesting a potential role in pathogenesis. Although coactivation of steroid-dependent transcription by SRA is accompanied by a proliferative response, overexpression is not in itself sufficient to induce turmorigenesis.
