Retina-derived POU domain factor 1 coordinates expression of genes relevant to renal and neuronal development

Int J Biochem Cell Biol. 2016 Sep:78:162-172. doi: 10.1016/j.biocel.2016.07.013. Epub 2016 Jul 15.

Abstract

Retina-derived POU domain Factor 1 (RPF-1), a member of POU transcription factor family, is encoded by POU6F2 gene, addressed by interstitial deletions at chromosome 7p14 in Wilms tumor (WT). Its expression has been detected in developing kidney and nervous system, suggesting an early role for this gene in regulating development of these organs. To investigate into its functions and determine its role in transcriptional regulation, we generated an inducible stable transfectant from HEK293 cells. RPF-1 showed nuclear localization, elevated stability, and transactivation of promoters featuring POU consensus sites, and led to reduced cell proliferation and in vivo tumor growth. By addressing the whole transcriptome regulated by its induction, we could detect a gross alteration of gene expression that is consistent with promoter occupancy predicted by genome-wide Chip-chip analysis. Comparison of bound regulatory regions with differentially expressed genes allowed identification of 217 candidate targets. Enrichment of divergent octamers in predicted regulatory regions revealed promiscuous binding to bipartite POUS and POUH consensus half-sites with intervening spacers. Gel-shift competition assay confirmed the specificity of RPF-1 binding to consensus motifs, and demonstrated that the Ser-rich region upstream of the POU domain is indispensable to achieve DNA-binding. Promoter-reporter activity addressing a few target genes indicated a dependence by RPF-1 on transcriptional response. In agreement with its expression in developing kidney and nervous system, the induced transcriptome appears to indicate a function for this protein in early renal differentiation and neuronal cell fate, providing a resource for understanding its role in the processes thereby regulated.

Keywords: Chromatin immunoprecipitation (ChiP); DNA binding protein; Developmental factor; Gene expression; POU transcription factor; Wilms tumor.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Active Transport, Cell Nucleus
  • Amino Acid Motifs
  • Cell Nucleus / metabolism
  • Cell Proliferation
  • Consensus Sequence
  • Gene Expression Regulation, Developmental*
  • HEK293 Cells
  • Humans
  • Kidney / growth & development*
  • Neurons / cytology*
  • POU Domain Factors / metabolism*
  • Transcription, Genetic

Substances

  • POU Domain Factors
  • POU6F2 protein, human