Abstract
Pax6 and c-Maf regulate multiple stages of mammalian lens development. Here, we identified novel distal control regions (DCRs) of the alphaA-crystallin gene, a marker of lens fiber cell differentiation induced by FGF-signaling. DCR1 stimulated reporter gene expression in primary lens explants treated with FGF2 linking FGF-signaling with alphaA-crystallin synthesis. A DCR1/alphaA-crystallin promoter (including DCR2) coupled with EGFP virtually recapitulated the expression pattern of alphaA-crystallin in lens epithelium and fibers. In contrast, the DCR3/alphaA/EGFP reporter was expressed only in 'late' lens fibers. Chromatin immunoprecipitations showed binding of Pax6 to DCR1 and the alphaA-crystallin promoter in lens chromatin and demonstrated that high levels of alphaA-crystallin expression correlate with increased binding of c-Maf and CREB to the promoter and of CREB to DCR3, a broad domain of histone H3K9-hyperacetylation extending from DCR1 to DCR3, and increased abundance of chromatin remodeling enzymes Brg1 and Snf2h at the alphaA-crystallin locus. Our data demonstrate a novel mechanism of Pax6, c-Maf and CREB function, through regulation of chromatin-remodeling enzymes, and suggest a multistage model for the activation of alphaA-crystallin during lens differentiation.
Publication types
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Research Support, N.I.H., Extramural
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Research Support, Non-U.S. Gov't
MeSH terms
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Adenosine Triphosphatases / metabolism
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Amino Acid Sequence
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Animals
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Cell Differentiation / physiology
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Chromatin / metabolism*
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Chromosomal Proteins, Non-Histone / metabolism
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Cyclic AMP Response Element-Binding Protein / genetics
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Cyclic AMP Response Element-Binding Protein / metabolism*
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DNA Helicases
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Eye Proteins / genetics
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Eye Proteins / metabolism*
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Gene Expression Regulation, Developmental*
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Genes, Reporter
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Histones / metabolism
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Homeodomain Proteins / genetics
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Homeodomain Proteins / metabolism*
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Humans
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Lens, Crystalline / anatomy & histology
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Lens, Crystalline / growth & development*
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Lens, Crystalline / metabolism
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Mice
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Mice, Transgenic
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Molecular Sequence Data
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Nuclear Proteins / metabolism
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PAX6 Transcription Factor
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Paired Box Transcription Factors / genetics
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Paired Box Transcription Factors / metabolism*
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Promoter Regions, Genetic
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Protein Binding
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Proto-Oncogene Proteins c-maf / genetics
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Proto-Oncogene Proteins c-maf / metabolism*
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RNA Polymerase II / metabolism
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Repressor Proteins / genetics
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Repressor Proteins / metabolism*
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Signal Transduction / physiology
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Tissue Culture Techniques
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Transcription Factors / metabolism
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Transcription, Genetic
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alpha-Crystallin A Chain / genetics
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alpha-Crystallin A Chain / metabolism*
Substances
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Chromatin
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Chromosomal Proteins, Non-Histone
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Creb1 protein, mouse
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Cyclic AMP Response Element-Binding Protein
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Eye Proteins
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Histones
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Homeodomain Proteins
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Maf protein, mouse
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Nuclear Proteins
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PAX6 Transcription Factor
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PAX6 protein, human
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Paired Box Transcription Factors
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Pax6 protein, mouse
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Proto-Oncogene Proteins c-maf
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Repressor Proteins
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Transcription Factors
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alpha-Crystallin A Chain
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RNA Polymerase II
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Adenosine Triphosphatases
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SMARCA4 protein, human
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Smarca4 protein, mouse
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Smarca5 protein, mouse
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DNA Helicases