Project description:Dendritic cells (DCs) are the most significant antigen presenting cells of the immune system, critical for the activation of naïve T cells. The pathways controlling DC development, maturation, and effector function therefore require precise regulation to allow for an effective induction of adaptive immune response. MYSM1 is a chromatin binding deubiquitinase (DUB), known to act as an activator of gene expression via its catalytic activity for monoubiquitinated histone H2A (H2A-K119ub), which is a highly abundant repressive epigenetic mark. MYSM1 is an important regulator of hematopoiesis in mouse and human, and a systemic constitutive loss of Mysm1 in mice results in a depletion of many hematopoietic progenitors, including DC precursors, with the downstream loss of most DC lineage cells. However, the roles of MYSM1 at the later checkpoints in DC development, maturation, activation, and effector function at present remain unknown. In the current work, using a range of mouse models (Mysm1flCreERT2, Mysm1flCD11c-cre, Mysm1DN), we further the understanding of MYSM1 functions in the DC lineage: assessing the requirement for MYSM1 in DC development independently of other complex developmental phenotypes, exploring its role at the later checkpoints in DC maintenance and activation in response to microbial stimulation, and testing the requirement for the DUB catalytic activity of MYSM1 in these processes. Surprisingly, we demonstrate that MYSM1 expression and catalytic activity in DCs are dispensable for the maintenance of DC numbers in vivo or for DC activation in response to microbial stimulation. In contrast, MYSM1 and its DUB catalytic activity in hematopoietic progenitors are essential for normal DC development, and its loss results not only in a severe depletion of DC lineage cells, but also in the production of functionally altered DCs, with a dysregulation of many housekeeping transcriptional programs and significantly altered responses to microbial stimulation.

Project description:Stem cell differentiation and lineage specification depend on coordinated programs of gene expression, but our knowledge of the chromatin modifying factors regulating these events remains incomplete. Ubiquitination of histone H2A (H2A-K119u) is a common chromatin modification associated with gene silencing, and controlled by the ubiquitin-ligase polycomb repressor complex 1 (PRC1) and H2A-deubiquitinating enzymes (H2A-DUBs). The roles of H2A-DUBs in mammalian development, stem cells, and haematopoiesis have not been addressed. Here we characterized an H2A-DUB targeted mouse line Mysm1-tm1a/tm1a and demonstrated defects in bone marrow haematopoiesis, resulting in lymphopenia, anemia, and thrombocytosis. Development of lymphocytes was impaired from the earliest stages of their differentiation; and there was also a depletion of erythroid cells and a defect in erythroid progenitor function. These phenotypes were due to a cell-intrinsic requirement for Mysm1 in the bone marrow. Importantly, Mysm1-tm1a/tm1a haematopoietic stem cells were functionally impaired, and this was associated with elevated levels of reactive oxygen species, γH2AX DNA damage marker, and p53 protein in the haematopoietic progenitors. Overall these data establish a role for Mysm1 in the maintenance of bone marrow stem cell function, in the control of oxidative stress and genetic stability in haematopoietic progenitors, and in the development of lymphoid and erythroid lineages. Total RNA from different mouse tissues (liver, bone marrow, brain) and cell types (embryonic fibroblasts - MEFs, and embryonic stem cells - ESCs) from wild type, Mysm1+/tm1a (heterozygous), and Mysm1tma1/tm1a (homozygous) mice was analyzed. Tissue and MEFs comparisons are between 3-4 animals per group; ESC comparisons are between three independently passaged samples of wild type, Mysm1+/tm1a, and Mysm1tma1/tm1aES-cells, all on C57BL/6 background. Full allele name: Mysm1tm1a(KOMP)WTSI . This Series includes the data from the tissues.

Project description:Stem cell differentiation and lineage specification depend on coordinated programs of gene expression, but our knowledge of the chromatin modifying factors regulating these events remains incomplete. Ubiquitination of histone H2A (H2A-K119u) is a common chromatin modification associated with gene silencing, and controlled by the ubiquitin-ligase polycomb repressor complex 1 (PRC1) and H2A-deubiquitinating enzymes (H2A-DUBs). The roles of H2A-DUBs in mammalian development, stem cells, and haematopoiesis have not been addressed. Here we characterized an H2A-DUB targeted mouse line Mysm1-tm1a/tm1a and demonstrated defects in bone marrow haematopoiesis, resulting in lymphopenia, anemia, and thrombocytosis. Development of lymphocytes was impaired from the earliest stages of their differentiation; and there was also a depletion of erythroid cells and a defect in erythroid progenitor function. These phenotypes were due to a cell-intrinsic requirement for Mysm1 in the bone marrow. Importantly, Mysm1-tm1a/tm1a haematopoietic stem cells were functionally impaired, and this was associated with elevated levels of reactive oxygen species, γH2AX DNA damage marker, and p53 protein in the haematopoietic progenitors. Overall these data establish a role for Mysm1 in the maintenance of bone marrow stem cell function, in the control of oxidative stress and genetic stability in haematopoietic progenitors, and in the development of lymphoid and erythroid lineages. Total RNA from different mouse tissues (liver, bone marrow, brain) and cell types (embryonic fibroblasts - MEFs, and embryonic stem cells - ESCs) from wild type, Mysm1+/tm1a (heterozygous), and Mysm1tma1/tm1a (homozygous) mice was analyzed. Tissue and MEFs comparisons are between 3-4 animals per group; ESC comparisons are between three independently passaged samples of wild type, Mysm1+/tm1a, and Mysm1tma1/tm1aES-cells, all on C57BL/6 background. Full allele name: Mysm1tm1a(KOMP)WTSI . This Series includes the data from the cells.

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MYSM1 acts as a novel co-activator of ERα via histone and non-histone deubiquitination to confer antiestrogen resistance in breast cancer

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