title: Dynamic changes in transcription factor complexes during erythroid differentiation revealed by quantitative proteomics.
abstract: During erythroid differentiation, beta-globin gene expression is regulated by the locus control region (LCR). The transcription factor NF-E2p18/MafK binds within this region and is essential for beta-globin expression in murine erythroleukemia (MEL) cells. Here we use the isotope-coded affinity tag (ICAT) technique of quantitative mass spectrometry to compare proteins interacting with NF-E2p18/MafK during differentiation. Our results define MafK as a 'dual-function' molecule that shifts from a repressive to an activating mode during erythroid differentiation. The exchange of MafK dimerization partner from Bach1 to NF-E2p45 is a key step in the switch from the repressed to the active state. This shift is associated with changes in the interaction of MafK with co-repressors and co-activators. Thus, our results suggest that in addition to its role as a cis-acting activator of beta-globin gene expression in differentiated erythroid cells, the LCR also promotes an active repression of beta-globin transcription in committed cells before terminal differentiation.
authors.affiliation: Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, Washington 98109, USA.
authors.forename: Marjorie
authors.initials: M
authors.lastname: Brand
authors.forename: Jeffrey A
authors.initials: JA
authors.lastname: Ranish
authors.forename: Nicolas T
authors.initials: NT
authors.lastname: Kummer
authors.forename: Joan
authors.initials: J
authors.lastname: Hamilton
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Igarashi
authors.forename: Claire
authors.initials: C
authors.lastname: Francastel
authors.forename: Tian H
authors.initials: TH
authors.lastname: Chi
authors.forename: Gerald R
authors.initials: GR
authors.lastname: Crabtree
authors.forename: Ruedi
authors.initials: R
authors.lastname: Aebersold
authors.forename: Mark
authors.initials: M
authors.lastname: Groudine
mesh_terms: D000818:Animals; D002454:Cell Differentiation; D002460:Cell Line; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D004912:Erythrocytes / Q000166:cytology / Q000378:metabolism; D050981:Erythroid-Specific DNA-Binding Factors; D004920:Erythropoiesis / Q000235:genetics / Q000502:physiology*; D018507:Gene Expression Regulation, Developmental; D005914:Globins / Q000235:genetics; D046911:Macromolecular Substances; D050985:MafK Transcription Factor; D051379:Mice; D008954:Models, Biological; D009687:Nuclear Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D040901:Proteomics; D014157:Transcription Factors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
chemical_list: D004268:DNA-Binding Proteins; D050981:Erythroid-Specific DNA-Binding Factors; D046911:Macromolecular Substances; D050985:MafK Transcription Factor; C494696:Mafk protein, mouse; D009687:Nuclear Proteins; D014157:Transcription Factors; D005914:Globins