title: Truncated SRA RNA derivatives inhibit estrogen receptor-α-mediated transcription.
abstract: The steroid receptor RNA activator (SRA) is a long non-coding RNA (lncRNA) that acts as a putative coactivator for steroid receptor-mediated transcription. A recent study showed that SRA RNA can be structurally dissected into four domains comprising various secondary structures, but the contribution of each domain to the coactivation ability of SRA RNA was previously unknown. Here, we assessed the functional contributions of the various domains of SRA. We examined the effects of each domain on the coactivation of estrogen receptor-α (ERα)-mediated transcription of a luciferase reporter gene in HeLa cells. Then the detailed domain analysis was focused on domain III (D3) not only with the reporter gene in HeLa cells, but also with ERα-responsive genes in MCF7 breast cancer cells. Domain deletion analysis showed that the deletion of any domain decreased the luciferase activity, and that deletion of D3 caused the largest decrease. This D3 deletion effect was not recovered by co-expression of D3 alone; moreover, the expression of D3 fragments (particularly helices H15-H18, which are highly conserved across vertebrates) inhibited luciferase expression in HeLa cells. Moreover, a fragment containing helices H15-H18 reduced ERα-responsive gene expression in MCF7 breast cancer cells. Our findings indicate that D3 inhibited ERα-mediated transcription of a reporter gene in HeLa cells and that helices H15-H18, as a core element responsible for the D3-driven inhibition, reduced expression of ERα-responsive genes in breast cancer cells.
authors.affiliation: Department of Chemistry, KAIST, Daejeon, 305-701, Korea.
authors.forename: Euihan
authors.initials: E
authors.lastname: Jung
authors.affiliation: Department of Chemistry, KAIST, Daejeon, 305-701, Korea.
authors.forename: Seonghui
authors.initials: S
authors.lastname: Jang
authors.affiliation: Department of Chemistry, KAIST, Daejeon, 305-701, Korea.
authors.forename: Jungmin
authors.initials: J
authors.lastname: Lee
authors.affiliation: Department of Chemistry, KAIST, Daejeon, 305-701, Korea.
authors.forename: Youngmi
authors.initials: Y
authors.lastname: Kim
authors.affiliation: Department of Chemistry, KAIST, Daejeon, 305-701, Korea.
authors.forename: Heegwon
authors.initials: H
authors.lastname: Shin
authors.affiliation: Department of Chemistry, KAIST, Daejeon, 305-701, Korea.
authors.forename: Hee-Sung
authors.initials: HS
authors.lastname: Park
authors.affiliation: Department of Chemistry, KAIST, Daejeon, 305-701, Korea. Younghoon.Lee@kaist.ac.kr.
authors.forename: Younghoon
authors.initials: Y
authors.lastname: Lee
mesh_terms: D002352:Carrier Proteins / Q000737:chemistry* / Q000235:genetics*; D047628:Estrogen Receptor alpha / Q000378:metabolism*; D005786:Gene Expression Regulation; D006367:HeLa Cells; D006801:Humans; D061986:MCF-7 Cells; D009690:Nucleic Acid Conformation; D017384:Sequence Deletion; D015398:Signal Transduction; D014158:Transcription, Genetic
chemical_list: D002352:Carrier Proteins; C506487:ESR1 protein, human; D047628:Estrogen Receptor alpha; C548898:steroid receptor RNA activator, human
keywords: Breast cancer cells; Coactivation; Domain III (D3); Estrogen receptor-α-mediated transcription; RNA inhibitor; SRA RNA