SATB1 family protein expressed during early erythroid differentiation modifies globin gene expression

Abstract

Special AT-rich binding protein 1 (SATB1) nuclear protein, expressed predominantly in T cells, regulates genes through targeting chromatin remodeling during T-cell maturation. Here we show SATB1 family protein induction during early human adult erythroid progenitor cell differentiation concomitant with ⑀-globin expression. Erythroid differentiation of human erythroleukemia K562 cells by hemin simultaneously increases ␥-globin and down-regulates SATB1 family protein and ⑀-globin gene expression. Chromatin immunoprecipitation using anti-SATB1 antibody shows selective binding in vivo in the ␤-globin cluster to the hypersensitive site 2 (HS2) in the locus control region (LCR) and to the ⑀-globin promoter. SATB1 overexpression increases ⑀-globin and decreases ␥-globin gene expression accompanied by histone hyperacetylation and hypomethylation in chromatin from the ⑀-globin promoter and HS2, and histone hypoacetylation and hypermethylation associated with the ␥-globin promoter. In K562 cells SATB1 family protein forms a complex with CREB-binding protein ( IntroductionThe human ␤-globin gene cluster on chromosome 11 consists of 5 developmentally specific genes for embryonic (⑀), fetal ( G ␥, A ␥), and adult (␦, ␤) globins. A strong enhancer, located in the far upstream region of the cluster called the locus control region (LCR), contains 5 DNase I hypersensitive (HS) sites and is able to enhance tissue-specific globin gene expression and provide a high level of transcription activity from human globin gene constructs in transgenic mice. Transcription factors such as erythroid Krüppel-like factor (EKLF), GATA-1, and NF-E2, that bind to the LCR and other regulatory elements, and promoters in the globin gene locus, have been reported to regulate chromatin histone acetylation by associating with histone acetyltransferases. [1][2][3] The LCR is required to increase the rate of transcription but may be dispensable for formation of an open chromatin domain of a downstream active globin gene in erythroid cells. 4,5 For globin gene expression, spatial organization of the ␤-globin cluster requires special interactions between distal transcriptional elements in the LCR and downstream active globin genes. Some developmental specificity between individual hypersensitive sites in the LCR and downstream globin genes is evident such as the interaction between HS2 and ⑀-globin for transcription activation. 6 Complex packaging of eukaryotic chromosomes in nuclei creates chromatin loops and matrix/scaffold attachment regions (MARs/SARs; the term MARs is used here), originally identified as gDNA fragments that remain tightly associated with saltextracted and DNase I-digested nuclei, have been postulated to be localized at the base of chromatin loops. 7 MARs identified by such criteria often contain a base-unpairing region (BUR), the DNA bases of which become continuously unpaired when subjected to negative superhelical strain. 8,9 Many candidate MARs in the ␤-globin cluster appear to be in regions of mass binding sites for transcription ...

Special AT-rich sequence binding protein 1 regulates the multidrug resistance and invasion of human gastric cancer cells

“…More recent studies have revealed that SATB1 is involved in the reconstruction of global genomes and regulates the expression of more than 1,000 genes. There is evidence to suggest that SATB1 modulates cell proliferation and lineage development and SATB1 is significant in breast cancer (7,11,12,20). The mechanism by which SATB1 contributes to the malignant phenotypes of tumor cells is poorly understood.…”

Scaffold/Matrix Attachment Regions (S/MARs): Relevance for Disease and Therapy

“…It is expressed predominantly (but not exclusively: see Wen et al 2005) in thymocytes where it represents one of the few gene products that are induced early upon peripheral T cell activation. A biological function emerged from the phenotype of SATB1 knockout mice, where SATB1 was found essential for orchestrating the spatial and temporal expression of a large number of T cell-and stage-specific genes: in the absence of SATB1, T cell development was severely impaired, and immature CD3-/CD4-/CD8-triple negative thymocytes were largely reduced in number.…”

SATB1 packages densely looped, transcriptionally active chromatin for coordinated expression of cytokine genes

“…For ChIP-loop assay, we performed chromatin immunoprecipitation before intramolecular ligation to identify the chromatin loop defined by specific protein. (c) The genomic DNA prepared for either ChIP-loop or 3C assay as described above was subjected to PCR amplification using various combination of forward and reverse primer pairs derived from the DNA fragments (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20). These PCR products derived from the 200kb cytokine locus using genomic DNA is designated Th2.…”

“…Furthermore, T cell development is arrested mainly at CD4 + /CD8 + (double-positive) stage 15 . SATB1 and its homolog SATB2 are expressed in multiple, but restricted cell types [20][21][22][23][24] , and some important post-translational modifications have been characterized for these proteins 25,26 .…”