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
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
The zinc finger transcription factor, Ikaros, is a central regulator of hematopoiesis. It is required for the development of the earliest B cell progenitors and at later stages for VDJ recombination and B cell recepto...The zinc finger transcription factor, Ikaros, is a central regulator of hematopoiesis. It is required for the development of the earliest B cell progenitors and at later stages for VDJ recombination and B cell receptors expression. Mature B cells rely on Ikaros to set the activation threshold for various stimuli, and to choose the correct antibody isotype during class switch recombination. Thus, Ikaros contributes to nearly every level of B cell differentiation and function.展开更多
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.
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.
基金Supported by La Ligue Contre le Cancer (équipe labellisée),l’ Agence Nationale de la Recherche and La Fondation pour la Recherche Médicale,with institute funding from INSERM,CNRS and l’Université de Strasbourg
文摘The zinc finger transcription factor, Ikaros, is a central regulator of hematopoiesis. It is required for the development of the earliest B cell progenitors and at later stages for VDJ recombination and B cell receptors expression. Mature B cells rely on Ikaros to set the activation threshold for various stimuli, and to choose the correct antibody isotype during class switch recombination. Thus, Ikaros contributes to nearly every level of B cell differentiation and function.
