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Mitsuhiro Ito

Publications and source records attributed to Mitsuhiro Ito.

At least 19 recordsLinked to original sources
PubMed2007

A kinase subunit of the human mediator complex, CDK8, positively regulates transcriptional activation.

The human thyroid hormone receptor-associated proteins (TRAP)/Mediator and related complexes mediate transcription through regulatory factors. To further understand the structural and functional diversity of these complexes we established three HeLa cell lines each expressing one of three epitope-tagged human TRAP/Mediator subunits, MED6, MED7, and CDK8 and isolated the complexes in which these subunits were contained by affinity and HPLC-gel filtration chromatography. The largest complexes from each cell line had a molecular mass of 1.5 MDa and possessed almost identical subunit compositions; we designated these complexes TRAP/Mediator-like complex 1 (TMLC1). Two potential subcomplexes were additionally observed: a 1-MDa complex from the CDK8-cell line (TMLC2) and a 600-kDa complex from the MED6-cell line (TMLC3). All three complexes regulated transcription in vitro; TMLC1 and TMLC3 augmented transcriptional activation, whereas TMLC2 repressed it. TMLC1 and TMLC2 phosphorylated RNA polymerase II (Pol II), but TMLC3 did not. Furthermore, TMLC1 predominantly interacted with the general transcription factors TFIIE, TFIIF, and TFIIH, which function during transcription initiation and the transition to elongation. In a final experiment, knockdown of CDK8 using RNA interference prevented transcriptional activation by Gal4-VP16 in a luciferase-assay. This, together with the effect of TMLC1 on transcription in vitro, suggests that CDK8 play positive roles in transcriptional activation.

Cyclin-Dependent Kinase 8↗
PubMed2005

A der(13)t(7;13)(p13;q14) with monoallelic loss of RB1 and D13S319 in myelodysplastic syndrome.

Deletions or translocations of chromosome band 13q14, the locus of the retinoblastoma gene (RB1), have been observed in a variety of hematological malignancies including myelodysplastic syndrome (MDS). We describe here a novel unbalanced translocation der(13)t(7;13)(p13;q14) involving 13q14 in a patient with MDS. A 66-year-old woman was diagnosed as having MDS, refractory anemia with excess of blasts (RAEB-1) because of 7.4% blasts and trilineage dysplasia in the bone marrow cells. G-banding and spectral karyotyping analyses showed complex karyotypes as follows: 46,XX,der(6)t(6;7)(q11;?),der(7)del(7)(?p13)t(6;7)(q?;q11)t(6;13)(q?;q?),der(13)t(7;13)(p13;q14). Fluorescence in situ hybridization (FISH) analyses demonstrated that one allele of the RB1 gene and the microsatellite locus D13S319, located at 13q14 and telomeric to the RB1 gene, was deleted. Considering other reported cases, our results indicate that submicroscopic deletions accompanying 13q14 translocations are recurrent cytogenetic aberrations in MDS. The RB1 gene or another tumor suppressor gene in the vicinity of D13S319, or both, may be involved in the pathogenesis of MDS with 13q14 translocations by monoallelic deletion.

Aged↗
PubMed2005

A new 19-metal-atom cluster [(Me2PhP)10Au12Ag7(NO3)9] with a nearly staggered-staggered M5 ring configuration.

New mixed metal clusters with M19 metal frameworks have been synthesized by NaBH4 reduction of Au(NO3)(PMe2Ph) together with AgNO3 in ethanol. Single crystal X-ray diffraction has revealed Au12Ag7 and Au17Ag2 metal skeletons for these clusters, which are best described in terms of bicapped pentagonal antiprismatic cages with a staggered-staggered M(5) ring configuration. These clusters connect the missing link between M13 icosahedral and M25 biicosahedral clusters providing a view of the cluster growth process. A TEM image of this cluster has been observed, which has clearly demonstrated single-sized nano-particles of less than 1.0 nm.

Crystallography, X-Ray↗
PubMed2005

The role of transcriptional coactivator TRAP220 in myelomonocytic differentiation.

The TRAP220 subunit of the thyroid hormone receptor-associated polypeptide transcription coactivator complex (TRAP/Mediator complex), mammalian counterpart of the yeast Mediator complex, is proposed to act on a variety of major and specific biological events through physical interactions with nuclear receptors. The vitamin D receptor (VDR) and retinoic acid receptor (RAR), coupled with retinoid X receptor (RXR), are nuclear receptors which have important roles for monopoiesis and granulopoiesis, respectively. In this study, we present the functional role of TRAP220 in nuclear receptor-mediated monopoiesis and granulopoiesis. The mouse Trap220(-/-) yolk sac hematopoietic progenitor cells were resistant to 1,25-dihydroxyvitamin D(3)-stimulated differentiation into monocytes/macrophages. Furthermore, flow cytometric analyses showed that HL-60 cells, human promyelocytic leukemia cell line, wherein TRAP220 was down-regulated, did not differentiate efficiently into monocytes and granulocytes by stimulation with 1,25-dihydroxyvitamin D(3) and all-trans retinoic acid, correspondingly. The expression of direct target genes of VDR or RAR, as well as the differentiation marker genes, was low in the knockdown cells. These results indicated a crucial role of TRAP220 in the optimal VDR- and RAR-mediated myelomonocytic differentiation processes in mammalian hematopoiesis.

Animals↗
PubMed2005

Successful treatment with defibrotide for sinusoidal obstruction syndrome after hematopoietic stem cell transplantation.

Sinusoidal obstruction syndrome (SOS) (formerly known as hepatic veno-occlusive disease (VOD)) is a life-threatening complication subsequent to hematopoietic stem cell transplantation. However, no completely satisfactory strategies for the treatment of SOS have been established yet. Defibrotide is a single-stranded polydeoxyribonucleotide with anti-thrombotic, anti-ischemic, anti-inflammatory and thrombolytic properties, but without systemic anticoagulant effects, and some encouraging results have been reported in western countries. We treated four patients with defibrotide for SOS, since there seemed to be no possibility to cure the patients with conventionally available treatments in Japan. All patients showed evidence of multiple organ failure at the start of the treatment. Defibrotide was administered intravenously in normal saline in four divided doses for 14 to 27 days. Three patients (75%) responded to the therapy, while one died of SOS and cytomegalovirus infection despite intensive therapy. None of the patients suffered from significant adverse effects such as severe hemorrhage. This is the first report dealing with the treatment with defibrotide of Japanese patients with SOS. Because defibrotide is considered to be promising for the treatment of SOS, it is important to start a phase II study as soon as possible.

Adult↗
PubMed2004

Omphalocele associated with a large multilobular umbilical cord pseudocyst.

The prevalence of umbilical cord cysts at 7-13 weeks' gestation is approximately 3%. More than 20% of such cases are complicated by structural defects and/or chromosomal abnormalities such as trisomy 18. These cysts usually have a single cavity and are <5 cm in size. Therefore, when an umbilical cord cyst is detected in the 2nd trimester, the examination of fetal karyotype is recommended. Omphaloceles are also well known to be complicated by many anomalies, especially trisomy 18. We report a case of an omphalocele associated with a large multilobular umbilical pseudocyst (diameter >5 cm) in a patient with a normal karyotype, 46XY. These anomalies were diagnosed by fetal ultrasonography. However, the cyst was difficult to diagnose as an umbilical cord pseudocyst because it was very large and multilobulated. At 38.5 weeks of gestation, the patient was delivered by Cesarean section. The cyst was resected, and the omphalocele was closed by staged surgeries. Pathologic diagnosis of the cyst was the degeneration of Wharton's jelly. This diagnosis was made by the absence of epithelial lining inside the cyst wall, since the existence of epithelial cells correlates with true cysts.

Cysts↗
PubMed2004

TIP30 interacts with an estrogen receptor alpha-interacting coactivator CIA and regulates c-myc transcription.

Deregulation of c-myc expression is implicated in the pathogenesis of many neoplasias. Estrogen receptor alpha (ERalpha) can increase the rate of c-myc transcription through the recruitment of a variety of cofactors to the promoter, yet the precise roles of these cofactors in transcription and tumorigenesis are largely unknown. We show here that a putative tumor suppressor TIP30, also called CC3 or Htatip2, interacts with an ERalpha-interacting coactivator CIA. Using chromatin immunoprecipitation assays, we demonstrate that TIP30 and CIA are distinct cofactors that are dynamically associated with the promoter and downstream regions of the c-myc gene in response to estrogen. Both TIP30 and CIA are recruited to the c-myc gene promoter by liganded ERalpha in the second transcription cycle. TIP30 overexpression represses ERalpha-mediated c-myc transcription, whereas TIP30 deficiency enhances c-myc transcription in both the absence and presence of estrogen. Ectopic CIA cooperates with TIP30 to repress ERalpha-mediated c-myc transcription. Moreover, virgin TIP30 knockout mice exhibit increased c-myc expression in mammary glands. Together, these results reveal an important role for TIP30 in the regulation of ERalpha-mediated c-myc transcription and suggest a mechanism for tumorigenesis promoted by TIP30 deficiency.

Acetyltransferases↗
PubMed2004

Involvement of casein kinase Iepsilon in cytokine-induced granulocytic differentiation.

Two closely related casein kinase I (CKI) isoforms, CKIdelta and CKIepsilon, are ubiquitously expressed in many human tissues, but their specific biologic function remains to be clarified. Here, we provide the first evidence that CKIepsilon is involved in hematopoietic cell differentiation. CKIepsilon, but not CKIdelta, was down-regulated along with human granulocytic differentiation. The specific down-regulation was observed in granulocyte colony-stimulating factor (G-CSF)-induced cell differentiation of murine interleukin-3 (IL-3)-dependent myeloid progenitor 32D cells. Introduction of wild-type (WT)-CKIepsilon into 32D cells inhibited the G-CSF-induced cell differentiation, whereas kinase-negative (KN)-CKIepsilon promoted the differentiation. Neither WT- nor KN-CKIepsilon affected IL-3-dependent cell growth. Moreover, introduction of WT- or KN-CKIdelta did not affect the cytokine-induced cell growth and differentiation. While G-CSF-induced activation of signal transducers and activators of transcription 3 (STAT3) was sustained by KN-CKIepsilon, STAT3 activation was attenuated by WT-CKIepsilon. This may be explained by the fact that the suppressor of cytokine signaling 3 (SOCS3) was stabilized by its physical association with CKIepsilon. Such stabilization by CKIepsilon was also seen in IL-3-induced beta-catenin. The stabilization of downstream components of cytokine and Wnt signaling by CKIepsilon might be critical for integration of several intracellular signaling pathways to a cell-specific biologic response in hematopoietic cell self-renewal.

Animals↗
PubMed2004

Unbalanced translocation der(11)t(11;12)(q23;q13): a new recurrent cytogenetic aberration in myelodysplastic syndrome with a complex karyotype.

Cytogenetic abnormalities are observed in approximately one half of cases of myelodysplastic syndrome (MDS). Partial or complete chromosome losses and chromosome gains are frequently found, but there is a relatively high incidence of unbalanced translocations in MDS. We describe here two cases of MDS with an unbalanced translocation, der(11)t(11;12)(q23;q13). Both patients were 69 years of age and diagnosed with refractory anemia with excess of blasts in transformation (RAEB-t) according to the high percentage of blasts in the peripheral blood. Cytoplasmic hypogranulation of neutrophils was evident as a dysplastic change. The blasts were positive for CD4 and CD41a as well as CD13, CD33, CD34 and HLA-DR in both cases. Chromosome analysis showed complex karyotypes including a der(11)t(1;11)(q11;p15)t(11;12)(q23;q13) in case 1 and der(11)t(11;12)(q23;q13) in case 2 plus several marker chromosomes. Spectral karyotyping confirmed the der(11)t(11; 12)(q23;q13) and clarified the origin of marker chromosomes, resulting in del(5q) and del(7q). Fluorescence in situ hybridization (FISH) analyses with a probe for the MLL gene demonstrated that the breakpoints at 11q23 were telomeric to the MLL gene in both cases. FISH also showed that the breakpoint at 11p15 of the case 1 was telomeric to the NUP98 gene. Considering another reported case, our results indicate that the der(11)t(11;12)(q23;q13) is a recurrent cytogenetic abnormality and may be involved in the pathogenesis of advanced-stage MDS.

Aged↗
PubMed2004

New phenotype of accessory scrotum with perineal lipoblastoma: coexistence of midperineal and lateral accessory scrotums.

We present the extremely rare phenotype of an accessory scrotum with an associated lipoblastoma. There was a coexistence of midperineal and lateral types. To our knowledge, this phenotype has never been reported. The lipoblastoma, which arose in the perineum, divided the moving labioscrotal swelling into three parts during early fetal life. This resulted in the specific anomaly in this patient.

Biopsy, Needle↗
PubMed2003

TIP30 deficiency increases susceptibility to tumorigenesis.

TIP30, also called CC3 or Htatip2, is a putative metastasis suppressor that promotes apoptosis and inhibits angiogenesis. Although TIP30 has several characteristic features of a tumor suppressor in in vitro analyses, tumor development as a result of TIP30 inactivation has not been demonstrated in vivo, and abnormal expression of TIP30 in human cancer has not been reported. Using genetically engineered mice and cells deficient in TIP30, we show that TIP30-deficient mice have a high incidence of hepatocellular carcinoma and other tumors, and loss of TIP30 enhances susceptibility of fibroblasts to transformation by the SV40 large T antigen. Furthermore, immunohistochemical analysis indicates that reduced TIP30 expression is associated with 33% of human hepatocellular carcinomas. Some of these carcinomas harbor missense mutations in the Tip30 gene, which cause abnormal expression of TIP30. Together, these results demonstrate that the Tip30 gene is a tumor susceptibility gene playing an important role in the suppression of hepatocarcinogenesis.

Acetyltransferases↗
PubMed2003

Successful repair of the esophagus in type-IV laryngo-tracheo-esophageal cleft using interposed jejunum.

The authors present a female patient of type-IV laryngo-tracheo-esophageal cleft (LTEC) who survived the definitive operation and was discharged from the hospital. Separation of the trachea and the esophagus was very difficult because they formed almost cylindrical common channel and multiple fistulae occurred after the operation. After multiple attempts of closure of the fistulae, one fistula near the carina remained, and the esophagus was reconstructed using interposed jejunum leaving some part of the esophagus connected to the fistula. Now she is practicing oral feeding. This is the fourth long-term survivor of type-IV LTEC in the international literature.

Abnormalities, Multiple↗
PubMed2003

Effective anti-viral therapy for hemophagocytic syndrome associated with B-cell lymphoma.

A rheumatoid arthritis (RA) patient treated with low-dose methotrexate (MTX) therapy suffered from hemophagocytic syndrome (HPS) associated with B-cell lymphoma (B-LAHS). Administration of acyclovir and intravenous immunoglobulin promptly resolved laboratory test abnormalities accompanied with HPS. Moreover, hemophagocytic histiocytes and lymphoma cells in the bone marrow disappeared without anti-cancer therapy. Two months after reintroduction of MTX for RA flare, lymphoma re-grew rapidly without bone marrow involvement and HPS. Two cycles of combination chemotherapy induced the lymphoma to a complete remission/unconfirmed (CRu), but then the chemotherapy was discontinued due to severe side effects. In this case, on the basis of RA and MTX induced immunosuppressive state, Epstein-Barr virus (EBV) infection was associated with the development of HPS and lymphoma. Anti-viral therapy alone was effective against HPS and lymphoma at initial presentation and improved her general condition. This case indicates that anti-cancer therapy should be preceded by anti-viral therapy and withdrawal of immunosuppressive therapy in patients under immunosuppressive therapy, as long as the clinical situation permits.

Acyclovir↗
PubMed2003

Morphologic, flow cytometric and cytogenetic evaluation of bone marrow involvement in B-cell lymphoma.

BACKGROUND AND OBJECTIVES: Flow cytometric immunophenotypic analysis (FC) and cytogenetic analysis are essential techniques for the diagnosis and classification of many hematologic disorders. The roles of these analyses in B-cell lymphoma to detect bone marrow (BM) involvement in clinical staging and to evaluate the effectiveness of treatments have not yet been determined. The aim of this study was to evaluate the usefulness of FC and cytogenetic analysis in the assessment of BM involvement in B-cell lymphoma. DESIGN AND METHODS: We retrospectively analyzed the usefulness of three-color FC and cytogenetic analysis in detecting BM involvement by examining 104 BM specimens from patients with B-cell lymphoma. RESULTS: By morphologic evaluation of BM biopsy (BMB), the BM was involved in 11 specimens (10.6%), not involved in 92 specimens (88.5%) and involvement could not be determined in 1 specimen (0.9%). FC identified a monoclonal B-cell population in 24 samples (23.1%). FC detected BM involvement in all but one BMB positive sample, and showed negative results in a BMB undetermined sample. Conclusively, FC found a monoclonal B-cell population in 14 of 92 BMB negative samples (15.2%). In particular, FC detected smaller amounts of BM involvement than did morphologic evaluation. Cytogenetic analysis revealed clonal abnormalities in only 9 of 104 samples (8.7%). However, 2 of these 9 samples were from patients with aggressive lymphoma with complex structural chromosomal abnormalities detectable only by cytogenetic analysis. INTERPRETATION AND CONCLUSIONS: Although morphologic evaluation of adequate amounts of BMB specimens remains essential for the evaluation of BM involvement, three-color FC is more sensitive in detecting BM disease than morphologic or cytogenetic analysis. Cytogenetic analysis seems to have low sensitivity and specificity, but this method may improve the detection of BM involvement in a small number of aggressive lymphomas that have many mitotic cells.

B-Lymphocytes↗
PubMed2002

Developmental expression of EphB6 in the thymus: lessons from EphB6 knockout mice.

A member of the largest family of receptor protein kinases, EphB6, lacks its intrinsic kinase activity, but it is expressed in normal human tissues. To investigate the physiological function of EphB6, we generated EphB6 deficient mice. EphB6(-/-) mice developed normally, revealed no abnormality in general appearance, and were fertile. Although a developmental increase of EphB6 in the fetal thymus was confirmed, T-cell development in various lymphoid organs of EphB6(-/-) mice was comparable to those of EphB6(+/+). Even in fetal thymus organ cultures, any developmental differences of EphB6(-/-) and EphB6(+/+) thymocytes were undetectable. The different binding characteristics to ephrin-Fc proteins between EphB6(-/-) and EphB6(+/+) thymocytes demonstrated that ephrin-B2 is the unique ligand for EphB6 among eight known ephrins. While EphB6 was a dominant receptor that binds to ephrin-B2 in adult thymocytes, fetal ones also expressed another EphB that binds to ephrin-B2. Overlapping expression of the EphB subfamily in the fetal thymus might compensate for the loss of EphB6 during the thymic development.

Animals↗
PubMed2002

The TRAP100 component of the TRAP/Mediator complex is essential in broad transcriptional events and development.

The multisubunit TRAP/Mediator complex is a mammalian counterpart of the yeast Mediator that shows diverse coactivation functions. Genetic ablation of the murine TRAP100 component of this complex has revealed that it is not essential for cell viability per se. However, null mutant mice die at an early developmental stage with severe malformations, and cultured TRAP100-deficient cells exhibit attenuated functions of a wide variety of transcriptional activators on ectopic reporters. The TRAP100-deficient TRAP/Mediator complex also lacks TRAP95 and TRAP150 beta/SUR2, which together with TRAP100 may form a submodule, and contains a reduced amount of SRB10/CDK8. Nevertheless, the residual complex shows unaltered binding both to RNA polymerase II and, with the exception of the oncoprotein E1A, to various activators. These findings suggest that TRAP/Mediator is broadly involved in transcription and that a TRAP100-containing submodule plays a secondary role, beyond primary activator interactions and RNA polymerase recruitment by the TRAP complex, in magnifying effects of activators on the general transcriptional machinery.

Abnormalities, Multiple↗