UTX maintains the functional integrity of the murine hematopoietic system by globally regulating aging-associated genes.

Epigenetic regulation is essential for the maintenance of the hematopoietic system, and its deregulation is implicated in hematopoietic disorders. In this study, UTX, a demethylase for lysine 27 on histone H3 (H3K27) and a component of COMPASS-like and SWI/SNF complexes, played an essential role in the hematopoietic system by globally regulating aging-associated genes. Utx-deficient (UtxΔ/Δ) mice exhibited myeloid skewing with dysplasia, extramedullary hematopoiesis, impaired hematopoietic reconstituting ability, and increased susceptibility to leukemia, which are the hallmarks of hematopoietic aging.

Acquired expression of in mice induces dysplastic myelopoiesis mimicking chronic myelomonocytic leukemia.

Chronic myelomonocytic leukemia (CMML) is a hematological malignancy characterized by uncontrolled proliferation of dysplastic myelomonocytes and frequent progression to acute myeloid leukemia (AML). We identified mutations in the gene, which encodes a negative regulator of cytokine signaling, in a subset of CMML patients. To investigate the contribution of mutant in CMML pathogenesis, we generated conditional knockin mice for that express wild-type in a steady state and inducibly express , a CMML-associated mutant.

Propagation of trimethylated H3K27 regulated by polycomb protein EED is required for embryogenesis, hematopoietic maintenance, and tumor suppression.

Polycomb repressive complex 2 (PRC2) catalyzes the monomethylation, dimethylation, and trimethylation of histone H3 Lys27 (H3K27) and acts as a central epigenetic regulator that marks the repressive chromatin domain. Embryonic ectoderm development (EED), an essential component of PRC2, interacts with trimethylated H3K27 (H3K27me3) through the aromatic cage structure composed of its three aromatic amino acids, Phe97, Trp364, and Tyr365. This interaction allosterically activates the histone methyltransferase activity of PRC2 and thereby propagates repressive histone marks.

Maintenance of the functional integrity of mouse hematopoiesis by EED and promotion of leukemogenesis by EED haploinsufficiency.

Polycomb repressive complex 2 (PRC2) participates in transcriptional repression through methylation of histone H3K27. The WD-repeat protein embryonic ectoderm development (EED) is a non-catalytic but an essential component of PRC2 and its mutations were identified in hematopoietic malignancies. To clarify the role(s) of EED in adult hematopoiesis and leukemogenesis, we generated Eed conditional knockout (Eed(Δ/Δ)) mice.

Fbxl10 overexpression in murine hematopoietic stem cells induces leukemia involving metabolic activation and upregulation of Nsg2.

We previously reported that deficiency for Samd9L, which was cloned as a candidate gene for -7/7q- syndrome, accelerated leukemia cooperatively with enhanced expression of a histone demethylase: F-box and leucine-rich repeat protein 10 (Fbxl10, also known as Jhdm1b, Kdm2b, and Ndy1). To further investigate the role of Fbxl10 in leukemogenesis, we generated transgenic (Tg) mice that overexpress Fbxl10 in hematopoietic stem cells (HSCs). Interestingly, Fbxl10 Tg mice developed myeloid or B-lymphoid leukemia with complete penetrance.

Acquired deficiency of A20 results in rapid apoptosis, systemic inflammation, and abnormal hematopoietic stem cell function.

A20 is a negative regulator of NF-κB, and mutational loss of A20 expression is involved in the pathogenesis of autoimmune diseases and B-cell lymphomas. To clarify the role of A20 in adult hematopoiesis, we generated conditional A20 knockout mice (A20(flox/flox) ) and crossed them with Mx-1Cre (MxCre (+)) and ERT2Cre (ERT2Cre (+)) transgenic mice in which Cre is inducibly activated by endogenous interferon and exogenous tamoxifen, respectively. A20(flox/flox) MxCre (+) (A20Mx) mice spontaneously exhibited myeloid proliferation, B cell apoptosis, and anemia with overproduction of pro-inflammatory cytokines.

CIZ1, a p21Cip1/Waf1-interacting protein, functions as a tumor suppressor in vivo.

CIZ1 is a nuclear protein involved in DNA replication and is also implicated in human diseases including cancers. To gain an insight into its function in vivo, we generated mice lacking Ciz1. Ciz1-deficient (Ciz1(-/-)) mice grew without any obvious abnormalities, and Ciz1(-/-) mouse embryonic fibroblasts (MEFs) did not show any defects in cell cycle status, cell growth, and DNA damage response.

Human CD72 splicing isoform responsible for resistance to systemic lupus erythematosus regulates serum immunoglobulin level and is localized in endoplasmic reticulum.

Background: CD72 is an inhibitory co-receptor expressed on B cells. We previously demonstrated significant association of the polymorphism of the CD72 gene with susceptibility to human systemic lupus erythematosus (SLE) in individuals carrying a SLE-susceptible FCGR2B genotype (FCGR2B-232Thr/Thr). The human CD72 locus generates a splicing isoform that lacks exon 8 (CD72Δex8) as well as full-length CD72 (CD72fl), and the CD72 polymorphism regulates exon 8 skipping.

Hemp, an mbt domain-containing protein, plays essential roles in hematopoietic stem cell function and skeletal formation.

To clarify the molecular pathways governing hematopoietic stem cell (HSC) development, we screened a fetal liver (FL) HSC cDNA library and identified a unique gene, hematopoietic expressed mammalian polycomb (hemp), encoding a protein with a zinc-finger domain and four malignant brain tumor (mbt) repeats. To investigate its biological role, we generated mice lacking Hemp (hemp(-/-)). Hemp(-/-) mice exhibited a variety of skeletal malformations and died soon after birth.

The role of the basic helix-loop-helix transcription factor Dec1 in the regulatory T cells.

Naturally occurring regulatory T (Treg) cells play a central role in the maintenance of immune homeostasis and in restraining the development of spontaneous inflammatory responses. However, the underlying mechanisms of Treg homeostasis remain incompletely understood. Of particular note, the IL-2Rα (CD25) is crucial for the homeostasis of Treg cells and the prevention of lymphoproliferative autoimmune disease.

p130Cas, Crk-associated substrate plays essential roles in liver development by regulating sinusoidal endothelial cell fenestration.

Unlabelled: p130Cas, Crk-associated substrate (Cas), is an adaptor/scaffold protein that plays a central role in actin cytoskeletal reorganization. We previously showed that mice in which Cas was deleted (Cas(-/-)) died in utero because of early cardiovascular maldevelopment. To further investigate the in vivo roles of Cas, we generated mice with a hypomorphic Cas allele lacking the exon 2-derived region (Cas(Deltaex2/Deltaex2)), which encodes Src homology domain 3 (SH3) of Cas.

Identification of CENP-V as a novel microtubule-associating molecule that activates Src family kinases through SH3 domain interaction.

The activation mechanisms of Src family kinases (SFKs) involve the dissociation of the intramolecular interaction between the Src homology (SH) 3 and kinase domain. This process is mediated by the intermolecular attack of outer ligands to the SH3 domain. By using a yeast two-hybrid screen, we isolated a relevant ligand involved in the activation mechanisms of SFKs.

Haploinsufficiency and acquired loss of Bcl11b and H2AX induces blast crisis of chronic myelogenous leukemia in a transgenic mouse model.

Chronic myelogenous leukemia (CML) is a hematological malignancy that begins as indolent chronic phase (CP) but inevitably progresses to fatal blast crisis (BC). p210BCR/ABL, a chimeric protein with enhanced kinase activity, initiates CML CP, and additional genetic alterations account for progression to BC, but the precise mechanisms underlying disease evolution are not fully understood. In the present study, we investigated the possible contribution of dysfunction of Bcl11b, a zinc-finger protein required for thymocyte differentiation, and of H2AX, a histone protein involved in DNA repair, to the transition from CML CP to BC.

Enhanced expression of p210BCR/ABL and aberrant expression of Zfp423/ZNF423 induce blast crisis of chronic myelogenous leukemia.

Chronic myelogenous leukemia (CML) is a hematopoietic disorder originating from p210BCR/ABL-transformed stem cells, which begins as indolent chronic phase (CP) but progresses into fatal blast crisis (BC). To investigate molecular mechanism(s) underlying disease evolution, CML-exhibiting p210BCR/ABL transgenic mice were crossed with BXH2 mice that transmit a replication-competent retrovirus. Whereas nontransgenic mice in the BXH2 background exclusively developed acute myeloid leukemia, p210BCR/ABL transgenic littermates developed nonmyeloid leukemias, in which inverse polymerase chain reaction detected 2 common viral integration sites (CISs).

Elevated intraocular pressure, optic nerve atrophy, and impaired retinal development in ODAG transgenic mice.

Purpose: In an earlier study, a cDNA was cloned that showed abundant expression in the eye at postnatal day (P)2 but was downregulated at P10; it was named ODAG (ocular development-associated gene). Its biological function was examined by generating and analyzing transgenic mice overexpressing ODAG (ODAG Tg) in the eye and by identifying ODAG-binding proteins.

Methods: Transgenic mice were generated by using the mouse Crx promoter.

Functional analysis of Src homology 3-encoding exon (exon 2) of p130Cas in primary fibroblasts derived from exon 2-specific knockout mice.

p130Cas (Cas, Crk-associated substrate) is an adaptor molecule composed of a Src homology 3 (SH3) domain, a substrate domain (SD) and a Src binding domain (SBD). The SH3 domain of Cas associates with focal adhesion kinase (FAK), but its role in cellular function has not fully been understood. To address this issue, we established and analyzed primary fibroblasts derived from mice expressing a truncated Cas lacking exon 2, which encodes the SH3 domain (Cas Deltaexon 2).

Fcepsilon- and Fcgamma-receptor signaling in diseases.

It has become increasingly clear that receptors for the immunoglobulin Fc region play pivotal roles in immune homeostasis and disease. This review describes the fine regulation of the high-affinity IgE-receptor (FcepsilonRI) signaling, especially focusing on the early events that are coordinately regulated by Src family protein tyrosine kinases (PTKs), FcepsilonRI beta-subunit, and membrane lipid rafts. Because allergen-mediated FcepsilonRI cross-linking leads to the synthesis and release of a variety of proinflammatory mediators and cytokines, the duration and amplitude of the signal need to be strictly controlled, and the counterbalancing signaling is provided by specialized inhibitory receptors and molecules.

Role of B cell inhibitory receptor polymorphisms in systemic lupus erythematosus: a negative times a negative makes a positive.

B lymphocytes play a pivotal role in the pathogenesis of systemic lupus erythematosus (SLE). Here, we will review our studies on the role of polymorphisms of two genes coding for B cell inhibitory receptors, FCGR2B and CD72. In FCGR2B, a single nucleotide polymorphism leading to a nonsynonymous substitution, Ile232Thr, within the transmembrane domain was identified, and a significant association of the 232Thr/Thr genotype with SLE was observed in Japanese, Thai and Chinese populations, while this allele was found to be rare in Caucasians.

FcgammaRIIB Ile232Thr transmembrane polymorphism associated with human systemic lupus erythematosus decreases affinity to lipid rafts and attenuates inhibitory effects on B cell receptor signaling.

The B cell inhibitory receptor FcgammaRIIB plays crucial roles in the maintenance of self-tolerance. We have identified a polymorphism FCGR2B c.695T>C that results in the non-conservative replacement of 232Ile at the transmembrane helix to Thr and demonstrated the association of the polymorphism with susceptibility to systemic lupus erythematosus (SLE) in Asians.

CD72 polymorphisms associated with alternative splicing modify susceptibility to human systemic lupus erythematosus through epistatic interaction with FCGR2B.

We previously reported association of FCGR2B-Ile232Thr with systemic lupus erythematosus (SLE) in three Asian populations. Because polymorphism of CD72, another inhibitory receptor of B cells, was associated with murine SLE, we identified human CD72 polymorphisms, tested their association with SLE and examined genetic interaction with FCGR2B in the Japanese (160 SLE, 277 controls), Thais (87 SLE, 187 controls) and Caucasians (94 families containing SLE members). Four polymorphisms and six rare variations were detected.