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Browsing by Author "Mahadevan, Jyothi"
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Item Efficient differentiation of murine embryonic stem cells requires the binding of CXXC finger protein 1 to DNA or methylated histone H3-Lys4(Elsevier, 2016-11) Mahadevan, Jyothi; Skalnik, David G.; Biology, School of ScienceMammalian CXXC finger protein 1 (Cfp1) is a DNA-binding protein that is a component of the Setd1 histone methyltransferase complexes and is a critical epigenetic regulator of both histone and cytosine methylation. Murine embryonic stem (ES) cells lacking Cfp1 exhibit a loss of histone H3-Lys4 tri-methylation (H3K4me3) at many CpG islands, and a mis-localization of this epigenetic mark to heterochromatic sub-nuclear domains. Furthermore, these cells fail to undergo cellular differentiation in vitro. These defects are rescued upon introduction of a Cfp1-expression vector. Cfp1 contains an N-terminal plant homeodomain (PHD), a motif frequently observed in chromatin associated proteins that functions as a reader module of histone marks. Here, we report that the Cfp1 PHD domain directly and specifically binds to histone H3K4me1/me2/me3 marks. Introduction of individual mutations at key Cfp1 PHD residues (Y28, D44, or W49) ablates this histone interaction both in vitro and in vivo. The W49A point mutation does not affect the ability of Cfp1 to rescue appropriate restriction of histone H3K4me3 to euchromatic sub-nuclear domains or in vitro cellular differentiation in Cfp1-null ES cells. Similarly, a mutated form of Cfp1 that lacks DNA-binding activity (C169A) rescues in vitro cellular differentiation. However, rescue of Cfp1-null ES cells with a double mutant form of Cfp1 (W49A, C169A) results in partially defective in vitro differentiation. These data define the Cfp1 PHD domain as a reader of histone H3K4me marks and provide evidence that this activity is involved in the regulation of lineage commitment in ES cells.Item The role of CFP1 in murine embryonic stem cell function and liver regeneration(2015-08) Mahadevan, Jyothi; Skalnik, David G.; Goebl, Mark G.; Harrington, Maureen A.; Herring, B. PaulCXXC finger protein 1 (Cfp1), a component of the Set1 histone methyltransferase complex, is a critical epigenetic regulator of both histone and cytosine methylation. Murine embryos lacking Cfp1 are unable to gastrulate and Cfp1-null embryonic stem (ES) cells fail to undergo cellular differentiation in vitro. However, expression of wild type Cfp1 in Cfp1-null ES cells rescues differentiation capacity, suggesting that dynamic epigenetic changes occurring during lineage specification require Cfp1. The domain structure of Cfp1 consists of a DNA binding CXXC domain and an N-terminal plant homeodomain (PHD). PHDs are frequently observed in chromatin remodeling proteins, functioning as reader modules for histone marks. However, the histone binding properties and underlying functional significance of Cfp1 PHD are largely unknown. My research revealed that Cfp1 PHD directly and specifically binds to histone H3K4me1/me2/me3 marks. A point mutation that abolishes binding to methylated H3K4 (W49A) does not affect rescue of cellular differentiation, but, point mutations that abolish both methylated H3K4 (W49A) and DNA (C169A) binding result in defective in vitro differentiation, indicating that PHD and CXXC exhibit redundant functions. The mammalian liver has the unique ability to regenerate following injury. Previous studies indicated that Cfp1 is essential for hematopoiesis in zebrafish and mice. I hypothesized that Cfp1 additionally plays a role in liver development and regeneration. To understand the importance of Cfp1 in liver development and regeneration, I generated a mouse line lacking Cfp1 specifically in the liver (Cfp1fl/fl Alb-Cre+). Around 40% of these mice display a wasting phenotype and die within a year. Livers of these mice have altered global H3K4me3 levels and often exhibit regenerative nodules. Most importantly, livers of these mice display an impaired regenerative response following partial hepatectomy. Collectively, these findings establish Cfp1 as an epigenetic regulator essential for ES cell function and liver homeostasis and regeneration.