Abstract
Expression of the gamma-globin gene is silenced in adult humans. However, certain point mutations in the gamma-globin gene promoter are capable of maintaining expression of this gene during adult erythropoiesis, a condition called non-deletion hereditary persistence of fetal hemoglobin (HPFH). Among these, the British form of HPFH carrying a T-->C point mutation at position -198 of the Agamma-globin gene promoter results in 4-10% fetal hemoglobin in heterozygotes. In this study, we used nuclear extracts from murine erythroleukemia cells to purify a protein complex that binds the HPFH -198 gamma-globin gene promoter. Members of this protein complex were identified by mass spectrometry and include DNMT1, the transcriptional coactivator p52, the protein SNEV, and RAP74 (the largest subunit of the general transcription factor IIF). Sp1, which was previously considered responsible for HPFH -198 gamma-globin gene activation, was not identified. The potential role of these proteins in the reactivation and/or maintenance of gamma-globin gene expression in the adult transcriptional environment is discussed.
Publication types
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Research Support, N.I.H., Extramural
MeSH terms
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Adult
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Animals
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Antibody Specificity
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Blotting, Western
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Cell Fractionation
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Cell Line, Tumor
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Chromatography, Affinity
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DNA (Cytosine-5-)-Methyltransferase 1
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DNA (Cytosine-5-)-Methyltransferases / immunology
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DNA (Cytosine-5-)-Methyltransferases / isolation & purification
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DNA (Cytosine-5-)-Methyltransferases / metabolism
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Fetal Hemoglobin / genetics*
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Gene Expression Regulation, Developmental*
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Globins / genetics*
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Humans
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Leukemia, Erythroblastic, Acute
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Mass Spectrometry
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Mice
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Mice, Transgenic
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Nuclear Matrix-Associated Proteins / immunology
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Nuclear Matrix-Associated Proteins / isolation & purification
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Nuclear Matrix-Associated Proteins / metabolism
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Point Mutation
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Promoter Regions, Genetic / physiology*
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Sp1 Transcription Factor / immunology
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Sp1 Transcription Factor / isolation & purification
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Sp1 Transcription Factor / metabolism
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Transcription Factors / immunology
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Transcription Factors / isolation & purification
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Transcription Factors / metabolism*
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Transcription Factors, TFII / immunology
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Transcription Factors, TFII / isolation & purification
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Transcription Factors, TFII / metabolism
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Transcriptional Activation
Substances
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Nuclear Matrix-Associated Proteins
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Sp1 Transcription Factor
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Transcription Factors
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Transcription Factors, TFII
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Globins
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Fetal Hemoglobin
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DNA (Cytosine-5-)-Methyltransferase 1
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DNA (Cytosine-5-)-Methyltransferases
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DNMT1 protein, human
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Dnmt1 protein, mouse
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transcription factor TFIIF