A role for the Werner syndrome protein in epigenetic inactivation of the pluripotency factor Oct4.
Werner syndrome (WS) is an autosomal recessive disorder, the hallmarks of which are premature aging and early onset of neoplastic diseases (Orren, 2006; Bohr, 2008). The gene, whose mutation underlies the WS phenotype, is called WRN. The protein encoded by the WRN gene, WRNp, has DNA helicase activity (Gray et al., 1997; Orren, 2006; Bohr, 2008; Opresko, 2008). Extensive evidence suggests that WRNp plays a role in DNA replication and DNA repair (Chen et al., 2003; Hickson, 2003; Orren, 2006; Turaga et al., 2007; Bohr, 2008). However, WRNp function is not yet fully understood. In this study, we show that WRNp is involved in de novo DNA methylation of the promoter of the Oct4 gene, which encodes a crucial stem cell transcription factor. We demonstrate that WRNp localizes to the Oct4 promoter during retinoic acid-induced differentiation of human pluripotent cells and associates with the de novo methyltransferase Dnmt3b in the chromatin of differentiating pluripotent cells. Depletion of WRNp does not affect demethylation of lysine 4 of the histone H3 at the Oct4 promoter, nor methylation of lysine 9 of H3, but it blocks the recruitment of Dnmt3b to the promoter and results in the reduced methylation of CpG sites within the Oct4 promoter. The lack of DNA methylation was associated with continued, albeit greatly reduced, Oct4 expression in WRN-deficient, retinoic acid-treated cells, which resulted in attenuated differentiation. The presented results reveal a novel function of WRNp and demonstrate that WRNp controls a key step in pluripotent stem cell differentiation.
Smith
Johanna A
JA
Division of Infectious Diseases, Thomas Jefferson University, Philadelphia, USA.
Ndoye
Abibatou M N
AM
Geary
Kyla
K
Lisanti
Michael P
MP
Igoucheva
Olga
O
Daniel
René
R
D015415:Biomarkers / Q000378:metabolism; D015704:CD4 Antigens / Q000235:genetics / Q000378:metabolism; D002454:Cell Differentiation / Q000187:drug effects / Q000235:genetics; D002460:Cell Line; D004248:DNA (Cytosine-5-)-Methyltransferases / Q000378:metabolism; D019175:DNA Methylation / Q000187:drug effects; D044127:Epigenesis, Genetic / Q000187:drug effects; D005090:Exodeoxyribonucleases / Q000378:metabolism*; D055785:Gene Knockdown Techniques; D020868:Gene Silencing / Q000187:drug effects; D006657:Histones / Q000378:metabolism; D018398:Homeodomain Proteins / Q000235:genetics; D006801:Humans; D008954:Models, Biological; D000071317:Nanog Homeobox Protein; D050814:Octamer Transcription Factor-3 / Q000235:genetics* / Q000378:metabolism; D039904:Pluripotent Stem Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D011401:Promoter Regions, Genetic / Q000235:genetics; D034741:RNA, Small Interfering / Q000378:metabolism; D053484:RecQ Helicases / Q000378:metabolism*; D014212:Tretinoin / Q000494:pharmacology; D000071657:Werner Syndrome Helicase; D055544:beta-Globins / Q000235:genetics / Q000378:metabolism; D000097584:DNA Methyltransferase 3B
D015415:Biomarkers; D015704:CD4 Antigens; D004248:DNA (Cytosine-5-)-Methyltransferases; D005090:Exodeoxyribonucleases; D006657:Histones; D018398:Homeodomain Proteins; D000071317:Nanog Homeobox Protein; D050814:Octamer Transcription Factor-3; D034741:RNA, Small Interfering; D053484:RecQ Helicases; D014212:Tretinoin; D000071657:Werner Syndrome Helicase; D055544:beta-Globins; D000097584:DNA Methyltransferase 3B; C486780:NANOG protein, human; C494173:POU5F1 protein, human; C098785:WRN protein, human