Synthetic reversal of epigenetic silencing

Karmella A. Haynes, Pamela A. Silver

Research output: Contribution to journalArticlepeer-review

42 Scopus citations


Controlling cell fate-determining gene expression is key to stem cell differentiation, tissue regeneration, and cancer therapy. To date, custom-built transcription factors recognize the information encoded in specific DNA sequences. Chromatin proteins undergo covalent modifications and form complexes that encode a second layer of information that determines proximal gene activity. Here, we employ a novel gene-targeting approach that exploits a specific chromatin modification to reactivate silenced loci in human cells. We used the human Polycomb chromatin protein and homologues from other species to construct modular synthetic transcription factors, called Pc-TFs, that recognize the repressive trimethyl-histone H3 lysine 27 (H3K27me3) signal and switch silenced genes to an active state. Pc-TF expression in U2OS osteosarcoma cells leads to increased transcription of the senescence locus CDKN2A (p16) and other loci in a chromodomain- and activation module-dependent manner, a switch to a senescence phenotype, and reduced cell proliferation. These results indicate that silenced developmental regulators can be reactivated by a synthetic transcription factor that interacts with chromatin rather than DNA, resulting in an altered cell state. As such, our work extends the flexibility of transcription factor engineering and is the first example of chromatin-mediated synthetic transcription factor targeting.

Original languageEnglish (US)
Pages (from-to)27176-27182
Number of pages7
JournalJournal of Biological Chemistry
Issue number31
StatePublished - Aug 5 2011
Externally publishedYes

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology


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