Browsing by Subject "Cellular differentiation"

Now showing 1 - 3 of 3
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    The histone demethylase LSD1 regulates inner ear progenitor differentiation through interactions with Pax2 and the NuRD repressor complex
    (Public Library of Science, 2018-01-25) Patel, Dharmeshkumar; Shimomura, Atsushi; Majumdar, Sreeparna; Holley, Matthew C.; Hashino, Eri; Otolaryngology -- Head and Neck Surgery, School of Medicine
    The histone demethylase LSD1 plays a pivotal role in cellular differentiation, particularly in silencing lineage-specific genes. However, little is known about how LSD1 regulates neurosensory differentiation in the inner ear. Here we show that LSD1 interacts directly with the transcription factor Pax2 to form the NuRD co-repressor complex at the Pax2 target gene loci in a mouse otic neuronal progenitor cell line (VOT-N33). VOT-N33 cells expressing a Pax2-response element reporter were GFP-negative when untreated, but became GFP positive after forced differentiation or treatment with a potent LSD inhibitor. Pharmacological inhibition of LSD1 activity resulted in the enrichment of mono- and di-methylation of H3K4, upregulation of sensory neuronal genes and an increase in the number of sensory neurons in mouse inner ear organoids. Together, these results identify the LSD1/NuRD complex as a previously unrecognized modulator for Pax2-mediated neuronal differentiation in the inner ear.
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    Identification of Specific Lysines and Arginines That Mediate Angiomotin Membrane Association
    (American Chemical Society, 2019-04-30) Hall, Le’Celia; Donovan, Emily; Araya, Michael; Idowa, Eniola; Jiminez-Segovia, Ilse; Folck, Anthony; Wells, Clark D.; Kimble-Hill, Ann C.; Biochemistry and Molecular Biology, School of Medicine
    The family of Angiomotin (Amot) proteins regulate several biological pathways associated with cellular differentiation, proliferation, and migration. These adaptor proteins target proteins to the apical membrane, actin fibers, or the nucleus. A major function of the Amot coiled-coil homology (ACCH) domain is to initiate protein interactions with the cellular membrane, particularly those containing phosphatidylinositol lipids. The work presented in this article uses several ACCH domain lysine/arginine mutants to probe the relative importance of individual residues for lipid binding. This identified four lysine and three arginine residues that mediate full lipid binding. Based on these findings, three of these residues were mutated to glutamates in the Angiomotin 80 kDa splice form and were incorporated into human mammary cell lines. Results show that mutating three of these residues in the context of full-length Angiomotin reduced the residence of the protein at the apical membrane. These findings provide new insight into how the ACCH domain mediates lipid binding to enable Amot proteins to control epithelial cell growth.
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    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. Paul
    CXXC 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.