The binding of the ubiquitous transcription factor Sp1 at the locus control region represses the expression of beta-like globin genes.
To investigate the function of transcription factor Sp1 in beta-like globin gene activation, we analyzed the recruitment of Sp1, fetal Krüppel-like factor 2 (FKLF2), and related factors at the human beta-globin locus in a human fetal liver and mouse erythroleukemia hybrid cell (A181gamma cell) that contains a single copy of human chromosome 11. Sp1 binds at the GT boxes of the cis-elements throughout the beta-locus, but it is phosphorylated and lost over DNase I hypersensitive site (HS)2, HS3, HS4, and the human beta-globin gene promoter after A181gamma cell differentiation. The binding of FKLF2 at HS2 and HS3 was unchanged. Histone deacetylase 1, which could be recruited by Sp1, is also lost over HS2 and HS3 after differentiation, resulting in the acetylation of histones 3 and 4 across the human beta-globin locus. We previously detected in vivo GT footprints over the beta-globin locus after A181gamma differentiation. Here, we report that after differentiation, the p300/CREB-binding protein-associated factor is recruited by FKLF2 to the locus control region to acetylate histones 3 and 4 at the human beta-globin gene locus. Our results suggest that Sp1 is an inhibitor of beta-like globin gene transcription during erythroid terminal differentiation. Its phosphorylation and release allow the erythroid-specific FKLF2 or erythroid Krüppel-like factor to interact with other erythroid-specific transcription factors to initiate the transcription of beta-like globin genes.
Feng
Dongxiao
D
Cardiovascular Research Institute and Department of Laboratory Medicine, University of California-San Francisco, San Francisco, CA 94143, USA.
Kan
Yuet Wai
YW
D000107:Acetylation; D000818:Animals; D015153:Blotting, Western; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism*; D045744:Cell Line, Tumor; D047369:Chromatin Immunoprecipitation; D020223:Chromosome Painting; D002880:Chromosomes, Human, Pair 11 / Q000235:genetics*; D017931:DNA Primers; D015536:Down-Regulation; D050881:E1A-Associated p300 Protein; D005914:Globins / Q000235:genetics / Q000378:metabolism*; D056284:Histone Deacetylase 1; D006655:Histone Deacetylases / Q000378:metabolism; D006657:Histones / Q000378:metabolism; D006801:Humans; D006822:Hybrid Cells; D051741:Kruppel-Like Transcription Factors; D019901:Locus Control Region / Q000235:genetics*; D051379:Mice; D009687:Nuclear Proteins / Q000378:metabolism; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016329:Sp1 Transcription Factor / Q000235:genetics / Q000378:metabolism*; D015534:Trans-Activators / Q000378:metabolism
D018797:Cell Cycle Proteins; D017931:DNA Primers; D006657:Histones; C486423:KLF13 protein, human; D051741:Kruppel-Like Transcription Factors; D009687:Nuclear Proteins; D012097:Repressor Proteins; D016329:Sp1 Transcription Factor; D015534:Trans-Activators; D005914:Globins; D050881:E1A-Associated p300 Protein; C494361:Ep300 protein, mouse; C484389:Hdac1 protein, mouse; D056284:Histone Deacetylase 1; D006655:Histone Deacetylases