Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P51532 (transcriptional activator)
 6,546 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Bax and Bcl2 are functionally antagonistic proteins which control apoptosis, whose expression in human tumours could be of prognostic value. We evaluated Bax and Bcl2 expression in 239 breast carcinomas (99 N0, 140 N1/2) with long term follow-up (median 79 months, range 11-140) in relation to clinico-pathologic parameters, clinical outcome, adjuvant therapy and expression of oestrogen receptor protein and p53. The prognostic value of Bax was investigated in the whole series of patients and in subgroups of homogeneously staged and treated patients (i.e., node-negative, N1/2 CMF-treated, N1/2 tamoxifen-treated). Bax immunostaining was cytoplasmic and heterogeneous. Cases were scored as Bax-positive if there were more than 20% reacting cells. High Bax expression was associated with positive nodal status (p = 0.03) and high Bcl2 expression (p = 0.01) and was more frequent in high-grade tumours. In the node-negative subgroup, Bax expression was associated with small tumour size. No association was seen with other parameters or with clinical outcome in any subgroup of patients. Since the apoptotic rate of a tumour is influenced by the ratio Bcl2/Bax, we investigated the combined effects of Bax and Bcl2 expression in relation to clinical outcome. However, no differences in survival were seen in the Bcl2-negative and Bcl2-positive groups when they were subdivided on the basis of the level of Bax expression and vice versa. In experimental systems, p53 is a direct transcriptional activator of the human bax gene. However, we could not observe any relation between Bax and p53 expression. We investigated whether the combined p53/Bax expression could have any prognostic value since it is predicted that tumours with normal p53 expression and concurrent high levels of Bax should be less aggressive and more susceptible to therapy. However, while p53 itself was of prognostic value, Bax expression was not related to prognosis in p53-negative or in p53-positive groups.
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PMID:Bax immunohistochemical expression in breast carcinoma: a study with long term follow-up. 949 51

mSin3A is a core component of a large multiprotein corepressor complex with associated histone deacetylase (HDAC) enzymatic activity. Physical interactions of mSin3A with many sequence-specific transcription factors has linked the mSin3A corepressor complex to the regulation of diverse signaling pathways and associated biological processes. To dissect the complex nature of mSin3A's actions, we monitored the impact of conditional mSin3A deletion on the developmental, cell biological, and transcriptional levels. mSin3A was shown to play an essential role in early embryonic development and in the proliferation and survival of primary, immortalized, and transformed cells. Genetic and biochemical analyses established a role for mSin3A/HDAC in p53 deacetylation and activation, although genetic deletion of p53 was not sufficient to attenuate the mSin3A null cell lethal phenotype. Consistent with mSin3A's broad biological activities beyond regulation of the p53 pathway, time-course gene expression profiling following mSin3A deletion revealed deregulation of genes involved in cell cycle regulation, DNA replication, DNA repair, apoptosis, chromatin modifications, and mitochondrial metabolism. Computational analysis of the mSin3A transcriptome using a knowledge-based database revealed several nodal points through which mSin3A influences gene expression, including the Myc-Mad, E2F, and p53 transcriptional networks. Further validation of these nodes derived from in silico promoter analysis showing enrichment for Myc-Mad, E2F, and p53 cis-regulatory elements in regulatory regions of up-regulated genes following mSin3A depletion. Significantly, in silico promoter analyses also revealed specific cis-regulatory elements binding the transcriptional activator Stat and the ISWI ATP-dependent nucleosome remodeling factor Falz, thereby expanding further the mSin3A network of regulatory factors. Together, these integrated genetic, biochemical, and computational studies demonstrate the involvement of mSin3A in the regulation of diverse pathways governing many aspects of normal and neoplastic growth and survival and provide an experimental framework for the analysis of essential genes with diverse biological functions.
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PMID:mSin3A corepressor regulates diverse transcriptional networks governing normal and neoplastic growth and survival. 1599 11

Early in vertebrate development, endodermal signals act on mesoderm to induce cardiogenesis. The F-type SOXs SOX7 and SOX18beta are expressed in the cardiogenic region of the early Xenopus embryo. Injection of RNAs encoding SOX7 or SOX18beta, but not the related F-type SOX, SOX17, leads to the nodal-dependent expression of markers of cardiogenesis in animal cap explants. Injection of morpholinos directed against either SOX7 or SOX18mRNAs lead to a partial inhibition of cardiogenesis in vivo, while co-injection of SOX7 and SOX18 morpholinos strongly inhibited cardiogenesis. SOX7 RNA rescued the effects of the SOX18 morpholino and visa versa, indicating that the proteins have redundant functions. In animal cap explants, it appears that SOX7 and SOX18 act indirectly through Xnr2 to induce mesodermal (Eomesodermin, Snail, Wnt11), organizer (Cerberus) and endodermal (endodermin, Hex) tissues, which then interact to initiate cardiogenesis. Versions of SOX7 and SOX18 with their C-terminal, beta-catenin interaction domains replaced by a transcriptional activator domain failed to antagonize beta-catenin activation of Siamois, but still induced cardiogenesis. These observations identify SOX7 and SOX18 as important, and previously unsuspected, regulators of cardiogenesis in Xenopus.
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PMID:SOX7 and SOX18 are essential for cardiogenesis in Xenopus. 1619 13

The leukemic fusion protein AML1-ETO occurs frequently in human acute myeloid leukemia (AML) and has received much attention over the past decade. An initial model for its pathogenetic effects emphasized the conversion of a hematopoietic transcriptional activator, RUNX1 (or AML1), into a leukemogenic repressor which blocked myeloid differentiation at the level of target gene regulation. This view has been absorbed into a larger picture of AML1-ETO pathogenesis, encompassing dysregulation of hematopoietic stem cell homeostasis at several mechanistic levels. Recent reports have highlighted a multifaceted capacity of AML1-ETO directly to inhibit key hematopoietic transcription factors that function as tumor suppressors at several nodal points during hematopoietic differentiation. A new model is presented in which AML1-ETO coordinates expansion of the stem cell compartment with diminished lineage commitment and with genome instability.
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PMID:Oncogenic pathways of AML1-ETO in acute myeloid leukemia: multifaceted manipulation of marrow maturation. 1712 17

Acquired chromosomal translocations can be identified in nearly 50% of human acute myeloid leukemias. The common chromosomal translocation in this disease is t(8;21) (q22;q22). It involves the aml1 (runx1) gene on chromosome 21 and the eto (mtg8, runx1t1) gene on chromosome 8 generating the aml1/eto fusion gene. An initial model for its pathogenesis emphasized the conversion of a hematopoietic transcriptional activator AML1 into a leukemogenic repressor which blocked myeloid differentiation at the level of target gene regulation. Aml1/eto fusion genes inhibit key hematopoietic transcription factor that function as tumor suppressors at several nodal point during hematopoietic differentiation. A new model is presented in which aml1/eto coordinates expansion of the stem cell compartment with diminished lineage commitment and with genome instability. In this review, the molecular role of aml1/eto fusion gene and his transcribed isoforms in regulating stem renewal, blocking hematopoietic differentiation and interacting with various lineage-specific transcription factors are summarized.
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PMID:[Advances on pathogenesis research of acute myeloid leukemia with t(8;21)-- review]. 2117 86

Myocyte enhancer binding factor 2B (MEF2B) is a transcriptional activator of the BCL6 proto-oncogene in normal germinal center (GC) B-cells. Limited data exists concerning its expression in B-cell lymphomas, and comparison with other GC-associated antigens is lacking. Its role in the differential diagnosis of B-cell lymphomas, particularly in the distinction of follicular lymphoma (FL) versus marginal zone lymphoma (MZL), remains to be determined. We evaluated MEF2B expression, in comparison with additional GC markers, LIM domain-only transcription factor 2 (LMO2), and human GC-associated lymphoma (HGAL), in a variety of B-cell lymphomas, with particular emphasis on their utility in differentiating FL from MZL. MEF2B was positive in all FL and Burkitt lymphomas, 8/9 mantle cell lymphomas, 2/24 splenic MZL, 1/10 chronic lymphocytic leukemia/small lymphocytic lymphomas, and 38/44 diffuse large B-cell lymphoma (DLBCL), but was negative in all extranodal MZL of mucosa-associated lymphoid tissue, nodal MZL, and B-lymphoblastic lymphomas. Focusing on low-grade FL versus MZL, MEF2B was 100% sensitive and 95% specific for FL, which was similar to BCL6, but superior to LMO2 (sensitivity 87%, specificity 86%) and HGAL (sensitivity 97%, specificity 86%). Importantly, MEF2B was positive in 4/4 FL with plasmacytoid differentiation, which were CD10, only weakly BCL6, and included 1 case that lacked both LMO2 and HGAL expression. MEF2B was positive in 22/25 (88%) GC-type DLBCL, but was also positive in 16/19 (61%) non-GC-type DLBCL. MEF2B shows superior sensitivity and specificity than LMO2 and HGAL in the differential diagnosis of FL versus MZL and is particularly useful in FL with plasmacytoid differentiation, which may have morphologic and immunophenotypic overlap with MZL. MEF2B, however, is not specific for GC-derived B-cell lymphomas as it is also apparently positive in most mantle cell lymphoma and many non-GC-type DLBCL.
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PMID:Comparison of Myocyte Enhancer Factor 2B Versus Other Germinal Center-associated Antigens in the Differential Diagnosis of B-Cell Non-Hodgkin Lymphomas. 2930 99