CXXC finger protein 1 contains redundant functional domains that support embryonic stem cell cytosine methylation, histone methylation, and differentiation.
CXXC finger protein 1 (Cfp1) is a regulator of both cytosine methylation and histone methylation. Murine embryonic stem (ES) cells lacking Cfp1 exhibit a decreased plating efficiency, decreased cytosine methylation, elevated global levels of histone H3-Lys4 trimethylation, and a failure to differentiate in vitro. Remarkably, transfection studies reveal that expression of either the amino half of Cfp1 (amino acids 1 to 367 [Cfp1(1-367)]) or the carboxyl half of Cfp1 (Cfp1(361-656)) is sufficient to correct all of the defects observed with ES cells that lack Cfp1. However, a point mutation (C169A) that abolishes DNA-binding activity of Cfp1 ablates the rescue activity of the Cfp1(1-367) fragment, and a point mutation (C375A) that abolishes the interaction of Cfp1 with the Setd1 histone H3-Lys4 methyltransferase complexes ablates the rescue activity of the Cfp1(361-656) fragment. Introduction of both the C169A and C375A point mutations ablates the rescue activity of the full-length Cfp1 protein. These results indicate that retention of either the Cfp1 DNA-binding domain or Setd1 interaction domain is required for Cfp1 rescue activity, and they illustrate the functional complexity of this critical epigenetic regulator. A model is presented for how epigenetic cross talk may explain the finding of redundant functional domains within Cfp1.
Tate
Courtney M
CM
Departments of Pediatrics and Biochemistry and Molecular Biology, Indiana University School of Medicine, 1044 West Walnut St., Room 327, Indianapolis, IN 46202, USA.
Lee
Jeong-Heon
JH
Skalnik
David G
DG
D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D002454:Cell Differentiation; D002460:Cell Line; D003596:Cytosine / Q000378:metabolism; D019175:DNA Methylation; D017931:DNA Primers / Q000235:genetics; D004268:DNA-Binding Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D053595:Embryonic Stem Cells / Q000166:cytology* / Q000378:metabolism*; D044127:Epigenesis, Genetic; D006657:Histones / Q000378:metabolism; D006801:Humans; D051379:Mice; D018345:Mice, Knockout; D008954:Models, Biological; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D010446:Peptide Fragments / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D017434:Protein Structure, Tertiary; D017386:Sequence Homology, Amino Acid; D015534:Trans-Activators / Q000737:chemistry* / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D014162:Transfection
C409062:CXXC1 protein, human; C501971:Cxxc1 protein, mouse; D017931:DNA Primers; D004268:DNA-Binding Proteins; D006657:Histones; D010446:Peptide Fragments; D015534:Trans-Activators; D003596:Cytosine