Hormone- and DNA Demethylation-Induced Relief of a Tissue-Specific and Developmentally Regulated Block in Transcriptional Elongation [Gene Regulation]

October 20th, 2014 by Rao, M. K., Matsumoto, Y., Richardson, M. E., Panneerdoss, S., Bhardwaj, A., Ward, J. M., Shanker, S., Bettegowda, A., Wilkinson, M. F.

Genome-wide studies have revealed that genes commonly have a high density of RNA polymerase II (Pol II) just downstream of the transcription start site. This has raised the possibility that genes are commonly regulated by transcriptional elongation, but this remains largely untested in vivo, particularly in vertebrates. Here, we show that the proximal promoter (Pp) from the Rhox5 homeobox gene recruits Pol II and begins elongating in all tissues and cell lines that we tested, but only completes elongation in a tissue-specific and developmentally regulated manner. Relief of the elongation block is associated with recruitment of the elongation factor P-TEFb, the co-activator GRIP1, the chromatin remodeling factor BRG1, and specific histone modifications. We provide evidence that two mechanisms relieve the elongation block at the Pp: demethylation and recruitment of androgen receptor (AR). Together, our findings support a model in which promoter proximal pausing helps confer tissue-specific and developmental gene expression through a mechanism relieved by DNA demethylation-dependent nuclear hormone receptor recruitment.
  • Posted in Journal of Biological Chemistry, Publications
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