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
Acute lymphoblastic leukemia (ALL) is characterized by immature and poorly differentiated B lymphocytes in large numbers in the blood. B cells are distinct from the cell types involved in their development (common lym...Acute lymphoblastic leukemia (ALL) is characterized by immature and poorly differentiated B lymphocytes in large numbers in the blood. B cells are distinct from the cell types involved in their development (common lymphoid progenitor cells, pro-B cells, pre-B cells, and mature cells). The process of B cell maturation depends on precise communication within the cell: signals activate specific genes that are essential for proper development. Errors in this intricate signaling network can lead to issues with B cell function and contribute to disease. B-lineage acute lymphoid leukemias, malignancies of precursor-stage B lymphoid cells inhibit lymphoid differentiation, leading to abnormal cell proliferation and survival. The process of developing leukemia (leukemogenesis) can be triggered by an overproduction of both hematopoietic stem cells (the cells that form all blood cells) and the immature versions of white blood cells called lymphoblasts. Acute lymphoblastic leukemia (ALL) with the presence of the Philadelphia chromosome (ALL Ph) is classified as a high-risk manifestation of the disease, this chromosome is the product of the reciprocal translocation, whose product is a BCR-ABL fusion protein. It is a highly active tyrosine kinase that can transform hematopoietic cells into cytokine-independent. Hyperphosphorylation cascades inhibit the differentiating function of IKZF1 as a tumor suppressor gene which leads to an abnormal proliferation of B cells due to the presence of the Philadelphia chromosome;it inhibits the differentiating process, leukemogenesis involving immature B cells in the bloodstream can result from the uncontrolled growth and division of hematopoietic stem cells and immature lymphoblasts (the precursors to B cells).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
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Acute lymphoblastic leukemia (ALL) is characterized by immature and poorly differentiated B lymphocytes in large numbers in the blood. B cells are distinct from the cell types involved in their development (common lymphoid progenitor cells, pro-B cells, pre-B cells, and mature cells). The process of B cell maturation depends on precise communication within the cell: signals activate specific genes that are essential for proper development. Errors in this intricate signaling network can lead to issues with B cell function and contribute to disease. B-lineage acute lymphoid leukemias, malignancies of precursor-stage B lymphoid cells inhibit lymphoid differentiation, leading to abnormal cell proliferation and survival. The process of developing leukemia (leukemogenesis) can be triggered by an overproduction of both hematopoietic stem cells (the cells that form all blood cells) and the immature versions of white blood cells called lymphoblasts. Acute lymphoblastic leukemia (ALL) with the presence of the Philadelphia chromosome (ALL Ph) is classified as a high-risk manifestation of the disease, this chromosome is the product of the reciprocal translocation, whose product is a BCR-ABL fusion protein. It is a highly active tyrosine kinase that can transform hematopoietic cells into cytokine-independent. Hyperphosphorylation cascades inhibit the differentiating function of IKZF1 as a tumor suppressor gene which leads to an abnormal proliferation of B cells due to the presence of the Philadelphia chromosome;it inhibits the differentiating process, leukemogenesis involving immature B cells in the bloodstream can result from the uncontrolled growth and division of hematopoietic stem cells and immature lymphoblasts (the precursors to B cells).
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.
