Silencing of Agamma-globin gene expression during adult definitive erythropoiesis mediated by GATA-1-FOG-1-Mi2 complex binding at the -566 GATA site.
Autonomous silencing of gamma-globin transcription is an important developmental regulatory mechanism controlling globin gene switching. An adult stage-specific silencer of the (A)gamma-globin gene was identified between -730 and -378 relative to the mRNA start site. A marked copy of the (A)gamma-globin gene inserted between locus control region 5' DNase I-hypersensitive site 1 and the epsilon-globin gene was transcriptionally silenced in adult beta-globin locus yeast artificial chromosome (beta-YAC) transgenic mice, but deletion of the 352-bp region restored expression. This fragment reduced reporter gene expression in K562 cells, and GATA-1 was shown to bind within this sequence at the -566 GATA site. Further, the Mi2 protein, a component of the NuRD complex, was observed in erythroid cells with low gamma-globin levels, whereas only a weak signal was detected when gamma-globin was expressed. Chromatin immunoprecipitation of fetal liver tissue from beta-YAC transgenic mice demonstrated that GATA-1, FOG-1, and Mi2 were recruited to the (A)gamma-globin -566 or (G)gamma-globin -567 GATA site when gamma-globin expression was low (day 18) but not when gamma-globin was expressed (day 12). These data suggest that during definitive erythropoiesis, gamma-globin gene expression is silenced, in part, by binding a protein complex containing GATA-1, FOG-1, and Mi2 at the -566/-567 GATA sites of the proximal gamma-globin promoters.
Harju-Baker
Susanna
S
Department of Biochemistry and Molecular Biology, MS 3030, University of Kansas Medical Center, 3901 Rainbow Boulevard, Kansas City, KS 66160, USA.
Costa
Flávia C
FC
Fedosyuk
Halyna
H
Neades
Renee
R
Peterson
Kenneth R
KR
D000818:Animals; D001483:Base Sequence; D001665:Binding Sites / Q000235:genetics; D018244:Chromosomes, Artificial, Yeast / Q000235:genetics; D017931:DNA Primers / Q000235:genetics; D004268:DNA-Binding Proteins / Q000378:metabolism; D004920:Erythropoiesis / Q000235:genetics*; D050980:GATA Transcription Factors / Q000378:metabolism; D050982:GATA1 Transcription Factor / Q000378:metabolism*; D015870:Gene Expression; D020868:Gene Silencing; D005914:Globins / Q000235:genetics*; D006655:Histone Deacetylases / Q000378:metabolism; D006801:Humans; D020014:K562 Cells; D046911:Macromolecular Substances; D056245:Mi-2 Nucleosome Remodeling and Deacetylase Complex; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D009687:Nuclear Proteins / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D014157:Transcription Factors / Q000378:metabolism*
D017931:DNA Primers; D004268:DNA-Binding Proteins; D050980:GATA Transcription Factors; D050982:GATA1 Transcription Factor; C494689:Gata1 protein, mouse; D046911:Macromolecular Substances; D009687:Nuclear Proteins; D012333:RNA, Messenger; D014157:Transcription Factors; C107310:Zfpm1 protein, mouse; D005914:Globins; D006655:Histone Deacetylases; D056245:Mi-2 Nucleosome Remodeling and Deacetylase Complex