Polo-like kinase 2 gene expression is regulated by the orphan nuclear receptor estrogen receptor-related receptor gamma (ERRγ)

Estrogen receptor-related receptor gamma (ERRγ) is a member of the nuclear receptor family of transcriptional activators. To date, the target genes and physiological functions of ERRγ are not well understood. In the current study, we identify that Plk2 is a novel target of ERRγ. Northern blot analysis showed that overexpression of ERRγ induced Plk2 expression in cancer cell lines. ERRγ activated the Plk2 gene promoter, and deletion and mutational analysis of the Plk2 promoter revealed that the ERRγ-response region is located between nucleotides (nt) −2327 and −2229 and −441 and −432 (relative to the transcriptional start site at +1). Electrophoretic mobility shift assay (EMSA) and chromatin immunoprecipitation (ChIP) analysis demonstrated that ERRγ binds directly to the Plk2 promoter. Overexpression of ERRγ in the presence of the mitotic inhibitor nocodazole significantly decreased apoptosis, and induced S-phase cell cycle progression through the induction of Plk2 expression. Taken together, these results demonstrated that Plk2 is a novel target of ERRγ, and suggest that this interaction is crucial for cancer cell proliferation.