Programmed silencing ofγ-globin genes in adult erythropoiesis is mediated by several chromatin remodeling complexes,which determine the stage-specific genome architecture in this region.Identification of cis-or trans...Programmed silencing ofγ-globin genes in adult erythropoiesis is mediated by several chromatin remodeling complexes,which determine the stage-specific genome architecture in this region.Identification of cis-or trans-acting mutations contributing to the diverse extent of fetal hemoglobin(Hb F)might illustrate the underlying mechanism ofγ-β-globin switching.Here,we recruit a cohort of 1142β-thalassemia patients and dissect the natural variants in the wholeβ-globin gene cluster through a targeted next-generation sequencing panel.A previously unreported SNP rs7948668,predicted to disrupt the binding motif of IKAROS as a key component of chromatin remodeling complexes,is identified to be significantly associated with higher levels of Hb F and age at onset.Gene-editing on this SNP leads to the elevation of Hb F in both HUDEP-2 and primary CD34+cells while the extent of elevation is amplified in the context ofβ-thalassemia mutations,indicating epistasis effects of the SNP in the regulation of Hb F.Finally,we perform ChIP-qPCR and 4C assays to prove that this variant disrupts the binding motif of IKAROS,leading to enhanced competitiveness of HBG promoters to locus control regions.This study highlights the significance of common regulatory SNPs and provides potential targets for treatingβ-hemoglobinopathy.展开更多
Ikaros (also known as Lyf-1) was initially described as a lymphoid-specific transcription factor.Although Ikaros has been shown to regulate hematopoietic stem cell renewal,as well as the development and function of ce...Ikaros (also known as Lyf-1) was initially described as a lymphoid-specific transcription factor.Although Ikaros has been shown to regulate hematopoietic stem cell renewal,as well as the development and function of cells from multiple hematopoietic lineages,including the myeloid lineage,Ikaros has primarily been studied in context of lymphoid development and malignancy.This review focuses on the role of Ikaros in myeloid cells.We address the importance of post-transcriptional regulation of Ikaros function;the emerging role of Ikaros in myeloid malignancy;Ikaros as a regulator of myeloid differentiation and function;and the selective expression of Ikaros isoform-x in cells with myeloid potential.We highlight the challenges of dissecting Ikaros function in lineage commitment decisions among lymphoidmyeloid progenitors that have emerged as a major myeloid differentiation pathway in recent studies,which leads to reconstruction of the traditional map of murine and human hematopoiesis.展开更多
The zinc finger motif was used as a vehicle for the initial discovery of Ikaros in the context of T-cell differentiation and has been central to all subsequent analyses of Ikaros function.The Ikaros gene is alternatel...The zinc finger motif was used as a vehicle for the initial discovery of Ikaros in the context of T-cell differentiation and has been central to all subsequent analyses of Ikaros function.The Ikaros gene is alternately spliced to produce several isoforms that confer diversity of function and consequently have complicated analysis of the function of Ikaros in vivo.Key features of Ikaros in vivo function are associated with six C2H2 zinc fingers;four of which are alternately incorporated in the production of the various Ikaros isoforms.Although no complete structures are available for the Ikaros protein or any of its family members,considerable evidence has accumulated about the structure of zinc fingers and the role that this structure plays in the functions of the Ikaros family of proteins.This review summarizes the structural aspects of Ikaros zinc fingers,individually,and in tandem to provide a structural context for Ikaros function and to provide a structural basis to inform the design of future experiments with Ikaros and its family members.展开更多
基金supported by the National Natural Science Foundation of China(U20A20353 to X.Xu and 81900185 to Y.Ye).
文摘Programmed silencing ofγ-globin genes in adult erythropoiesis is mediated by several chromatin remodeling complexes,which determine the stage-specific genome architecture in this region.Identification of cis-or trans-acting mutations contributing to the diverse extent of fetal hemoglobin(Hb F)might illustrate the underlying mechanism ofγ-β-globin switching.Here,we recruit a cohort of 1142β-thalassemia patients and dissect the natural variants in the wholeβ-globin gene cluster through a targeted next-generation sequencing panel.A previously unreported SNP rs7948668,predicted to disrupt the binding motif of IKAROS as a key component of chromatin remodeling complexes,is identified to be significantly associated with higher levels of Hb F and age at onset.Gene-editing on this SNP leads to the elevation of Hb F in both HUDEP-2 and primary CD34+cells while the extent of elevation is amplified in the context ofβ-thalassemia mutations,indicating epistasis effects of the SNP in the regulation of Hb F.Finally,we perform ChIP-qPCR and 4C assays to prove that this variant disrupts the binding motif of IKAROS,leading to enhanced competitiveness of HBG promoters to locus control regions.This study highlights the significance of common regulatory SNPs and provides potential targets for treatingβ-hemoglobinopathy.
文摘Ikaros (also known as Lyf-1) was initially described as a lymphoid-specific transcription factor.Although Ikaros has been shown to regulate hematopoietic stem cell renewal,as well as the development and function of cells from multiple hematopoietic lineages,including the myeloid lineage,Ikaros has primarily been studied in context of lymphoid development and malignancy.This review focuses on the role of Ikaros in myeloid cells.We address the importance of post-transcriptional regulation of Ikaros function;the emerging role of Ikaros in myeloid malignancy;Ikaros as a regulator of myeloid differentiation and function;and the selective expression of Ikaros isoform-x in cells with myeloid potential.We highlight the challenges of dissecting Ikaros function in lineage commitment decisions among lymphoidmyeloid progenitors that have emerged as a major myeloid differentiation pathway in recent studies,which leads to reconstruction of the traditional map of murine and human hematopoiesis.
文摘The zinc finger motif was used as a vehicle for the initial discovery of Ikaros in the context of T-cell differentiation and has been central to all subsequent analyses of Ikaros function.The Ikaros gene is alternately spliced to produce several isoforms that confer diversity of function and consequently have complicated analysis of the function of Ikaros in vivo.Key features of Ikaros in vivo function are associated with six C2H2 zinc fingers;four of which are alternately incorporated in the production of the various Ikaros isoforms.Although no complete structures are available for the Ikaros protein or any of its family members,considerable evidence has accumulated about the structure of zinc fingers and the role that this structure plays in the functions of the Ikaros family of proteins.This review summarizes the structural aspects of Ikaros zinc fingers,individually,and in tandem to provide a structural context for Ikaros function and to provide a structural basis to inform the design of future experiments with Ikaros and its family members.
