High-throughput cell-based screening reveals a role for ZNF131 as a repressor of ERalpha signaling.

Background: Estrogen receptor alpha (ERalpha) is a transcription factor whose activity is affected by multiple regulatory cofactors. In an effort to identify the human genes involved in the regulation of ERalpha, we constructed a high-throughput, cell-based, functional screening platform by linking a response element (ERE) with a reporter gene. This allowed the cellular activity of ERalpha, in cells cotransfected with the candidate gene, to be quantified in the presence or absence of its cognate ligand E2.

Results: From a library of 570 human cDNA clones, we identified zinc finger protein 131 (ZNF131) as a repressor of ERalpha mediated transactivation. ZNF131 is a typical member of the BTB/POZ family of transcription factors, and shows both ubiquitous expression and a high degree of sequence conservation. The luciferase reporter gene assay revealed that ZNF131 inhibits ligand-dependent transactivation by ERalpha in a dose-dependent manner. Electrophoretic mobility shift assay clearly demonstrated that the interaction between ZNF131 and ERalpha interrupts or prevents ERalpha binding to the estrogen response element (ERE). In addition, ZNF131 was able to suppress the expression of pS2, an ERalpha target gene.

Conclusion: We suggest that the functional screening platform we constructed can be applied for high-throughput genomic screening candidate ERalpha-related genes. This in turn may provide new insights into the underlying molecular mechanisms of ERalpha regulation in mammalian cells.