A positive role for NLI/Ldb1 in long-range beta-globin locus control region function.
Long-range interactions between distant regulatory elements, such as enhancers, and their target genes underlie the specificity of gene expression in many developmentally regulated gene families. NLI/Ldb1, a widely expressed nuclear factor, is a potential mediator of long-range interactions. Here, we show that NLI/Ldb1 and erythroid-binding partners GATA-1/SCL/LMO2 bind in vivo to the beta-globin locus control region (LCR). The C-terminal LIM interaction domain of NLI is required for formation of the complex on chromatin. Loss of the LIM domain converts NLI into a dominant-negative inhibitor of globin gene expression, and knockdown of NLI by using shRNA results in failure to activate beta-globin expression. Kinetic studies reveal that the NLI/GATA-1/SCL/LMO2 complex is detected at the beta-globin promoter coincident with RNA Pol II recruitment, beta-globin transcription, and chromatin loop formation during erythroid differentiation, providing evidence that NLI facilitates long-range gene activation.
Song
Sang-Hyun
SH
Laboratory of Cellular and Developmental Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA.
Hou
Chunhui
C
Dean
Ann
A
D048868:Adaptor Proteins, Signal Transducing; D051792:Basic Helix-Loop-Helix Proteins / Q000235:genetics / Q000378:metabolism; D002454:Cell Differentiation; D002843:Chromatin / Q000378:metabolism; D047369:Chromatin Immunoprecipitation; D004268:DNA-Binding Proteins / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000378:metabolism; D041905:Erythroid Cells / Q000378:metabolism; D050982:GATA1 Transcription Factor / Q000235:genetics / Q000378:metabolism; D005786:Gene Expression Regulation; D005914:Globins / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D015151:Immunoblotting; D047468:Immunoprecipitation; D007700:Kinetics; D060588:LIM Domain Proteins; D019901:Locus Control Region; D008667:Metalloproteins / Q000235:genetics / Q000378:metabolism; D011401:Promoter Regions, Genetic; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000378:metabolism; D012319:RNA Polymerase II / Q000378:metabolism; D034741:RNA, Small Interfering / Q000494:pharmacology; D012045:Regulatory Sequences, Nucleic Acid; D000073942:T-Cell Acute Lymphocytic Leukemia Protein 1; D014157:Transcription Factors; D014158:Transcription, Genetic; D015533:Transcriptional Activation; D014407:Tumor Cells, Cultured
D048868:Adaptor Proteins, Signal Transducing; D051792:Basic Helix-Loop-Helix Proteins; D002843:Chromatin; D004268:DNA-Binding Proteins; D050982:GATA1 Transcription Factor; D005914:Globins; D060588:LIM Domain Proteins; D008667:Metalloproteins; D011518:Proto-Oncogene Proteins; D012319:RNA Polymerase II; D034741:RNA, Small Interfering; D000073942:T-Cell Acute Lymphocytic Leukemia Protein 1; D014157:Transcription Factors; C494688:GATA1 protein, human; C486312:LDB1 protein, human; C085117:LMO2 protein, human; C067143:TAL1 protein, human