Zic3 Enhances the Generation of Mouse Induced Pluripotent Stem Cells

Abstract

Zinc finger protein of the cerebellum (Zic)3, a member of Gli family of transcription factors (TFs), is essential for maintaining pluripotency of embryonic stem cells (ESCs) and has been reported to activate TF Nanog in an Oct4/Sox2-independent manner. Previously, we showed that Zic3 (Z), in combination with the Yamanka factors OCT4, SOX2, and KLF4 (OSK), induces neural progenitor-like cells from human fibroblasts. However, a similar combination of TFs (OSKZ) transduced in mouse embryonic fibroblasts resulted in enhanced induced pluripotent stem cells (iPSCs) formation compared with OSK alone, but not neuroprogenitors. OSKZ-derived iPSCs are indistinguishable from mESCs in colony morphology, expression of alkaline phosphatase and pluripotency genes, and embryoid body and teratoma formation. Zic3 activates the transcription of Nanog, a key pluripotency regulator, as evidenced by a luciferase promoter assay. During the course of iPSC derivation, Zic3-mediated enhanced expression of Nanog and Tbx3, gene known to enhance iPSCs derivation, is observed. Not only does Zic3 enhance the reprogramming efficiency, but also reactivation of the endogenous Zic3 protein is essential for the generation of iPSCs, as knockdown of Zic3 during the iPSC generation with OSKM significantly reduced the number of colonies. Together, our result uncovers an important role of Zic3 in generating mouse iPSCs.

Models of human core transcriptional regulatory circuitries

“…2B). FOXO1 and ZIC3 have previously been shown to be essential for the maintenance of pluripotency (Lim et al 2007;Zhang et al 2011;Declercq et al 2013). In hESCs, FOXO1 regulates POU5F1 and SOX2 expression .…”

“…In hESCs, FOXO1 regulates POU5F1 and SOX2 expression . ZIC3 directly activates Nanog expression in mouse ESCs (mESCs) and can contribute to reprogramming of human fibroblasts into an induced pluripotent state (Lim et al 2007;Declercq et al 2013). NR5A1 (also known as SF1) and RARG can influence the pluripotent state (Guo and Smith 2010;Wang et al 2011), and both bind to regulatory regions of the POU5F1 gene and regulate its expression (Barnea and Bergman 2000;Yang et al 2007;Guo and Smith 2010).…”

The T-Box transcription factor 3 in development and cancer

“…In addition, Tbx3 was shown to improve the generation of porcine iPSCs when co-expressed with Oct4, Sox2, Kruppel-like factor 4 (Klf4) and c-Myc (36). Furthermore, iPSC formation increased when Tbx3 expression was enhanced by Zinc finger protein of the cerebellum 3 (Zic3) (37). Ectopic overexpression of Tbx3 in the atria of the adult mouse heart was also shown to reprogramme mature differentiated atrial myocytes into a more naïve pacemaker phenotype by repressing genes required for the working myocardial function and stimulating genes required for pacemaker functions (38).…”

Epigenetic reprogramming induces the expansion of cord blood stem cells

“…The ZIC3 gene has been identified as a target of OCT4, SOX2, and NANOG in ES cells. ZIC3 overlaps with the OCT4, NANOG, and SOX2 transcriptional networks, is important in maintaining pluripotency, and can directly modulate the expression of NANOG (48,53,54).…”