Open AccessDNA Methyltransferase Protein Synthesis Is Reduced in CXXC Finger Protein 1–Deficient Embryonic Stem Cells
Author(s) -
Jill Sergesketter Butler,
Lakshmi Reddy Palam,
Courtney M. Tate,
Jeremy R. Sanford,
Ronald C. Wek,
David G. Skalnik
Publication year - 2009
Publication title -
dna and cell biology
Language(s) - English
Resource type - Journals
eISSN - 1557-7430
pISSN - 1044-5498
DOI - 10.1089/dna.2009.0854
Subject(s) - biology , embryonic stem cell , stem cell , microbiology and biotechnology , methyltransferase , dna , nuclear protein , genetics , gene , transcription factor , methylation
CXXC finger protein 1 (CFP1) binds to unmethylated CpG dinucleotides and is required for embryogenesis. CFP1 is also a component of the Setd1A and Setd1B histone H3K4 methyltransferase complexes. Murine embryonic stem (ES) cells lacking CFP1 fail to differentiate, and exhibit a 70% reduction in global genomic cytosine methylation and a 50% reduction in DNA methyltransferase (DNMT1) protein and activity. This study investigated the underlying mechanism for reduced DNMT1 expression in CFP1-deficient ES cells. DNMT1 transcript levels were significantly elevated in ES cells lacking CFP1, despite the observed reduction in DNMT1 protein levels. To address the posttranscriptional mechanisms by which CFP1 regulates DNMT1 protein activity, pulse/chase analyses were carried out, demonstrating a modest reduction in DNMT1 protein half-life in CFP1-deficient ES cells. Additionally, global protein synthesis was decreased in ES cells lacking CFP1, contributing to a reduction in the synthesis of DNMT1 protein. ES cells lacking CFP1 were found to contain elevated levels of phosphorylated eIF2alpha, and an accompanying reduction in translation initiation as revealed by a lower level of polyribosomes. These results reveal a novel role for CFP1 in the regulation of translation initiation, and indicate that loss of CFP1 function leads to decreased DNMT1 protein synthesis and half-life.