Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0023473 (chronic myeloid leukemia)
 18,916 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A transcriptional enhancer has been mapped to a region 5.5 kilobases 3' of the C beta 2 gene in the human T-cell receptor (TCR) beta-chain locus. Transient transfections allowed localization of enhancer activity to a 480-base-pair HincII-XbaI restriction enzyme fragment. The TCR beta enhancer was active on both the minimal simian virus 40 promoter and a TCR beta variable gene promoter in both TCR alpha/beta + and TCR gamma/delta + T cells. It displayed significantly less activity in Epstein-Barr virus-transformed B cells and K562 chronic myelogenous leukemia cells and no activity in HeLa fibroblasts. DNA sequence analysis revealed that the enhancer contains a consensus immunoglobulin kappa E2 motif, as well as an AP-1-binding site and a cyclic AMP response element. DNase I footprint analyses using Jurkat T-cell nuclear extracts allowed the identification of five nuclear protein-binding sites, T beta 1 to T beta 5, within the enhancer element. Deletion and in vitro mutagenesis studies demonstrated that the T beta 2- and T beta 3- and T beta 4-binding sites are each required for full transcriptional enhancer activity. In contrast, deletion of the T beta 1- and T beta 5-binding sites had essentially no effect on enhancer function. Electrophoretic mobility shift assays demonstrated that TCR alpha/beta + and TCR gamma/delta + T cells expressed T beta 2-, T beta 3-, and T beta 4-binding activities. In contrast, non-T-cell lines, in which the enhancer was inactive, each lacked expression of at least one of these binding activities. TCR alpha and beta gene expression may be regulated by a common set of T-cell nuclear proteins in that the T beta 2 element binding a set of cyclic AMP response element-binding proteins that are also bound by the T alpha 1 element of the human TCR alpha enhancer and the decamer element present in a large number of human and murine TCR beta promoters. Similarly, the T beta 5 TCR beta-enhancer element and the T alpha 2 TCR alpha-enhancer element bind at least one common T-cell nuclear protein. Taken together, these results suggest that TCR beta gene expression is regulated by the interaction of multiple T cell nuclear proteins with a transcriptional enhancer element located 3' of the C beta 2 gene and that some of these proteins may be involved in the coordinate regulation of TCR alpha and beta gene expression.
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PMID:Identification and functional characterization of the human T-cell receptor beta gene transcriptional enhancer: common nuclear proteins interact with the transcriptional regulatory elements of the T-cell receptor alpha and beta genes. 214 10

Cytoplasmic protein from peripheral blood myeloid cells of chronic myelogenous leukemia (CML) patients altered the electrophoretic mobility of complexes formed between nuclear proteins and interferon-inducible transcriptional enhancers. Immature myeloid marrow cells (blasts and promyelocytes) have a higher level of this activity than do mature myeloid marrow cells (bands and polys). This activity, which is not detectable in the peripheral blood cells of normal individuals, is at least 50-fold higher in CML marrow blasts and promyelocytes than that found in marrow blasts and promyelocytes of normal individuals. This activity was inhibited by in vivo incubation of immature myeloid cells with the phosphatase inhibitor, sodium orthovanadate (0.2 mM), and by adding orthovanadate (20 mM) directly to cytoplasmic proteins of myeloid cells. Interferon-alpha (1,000 U/ml) reduced the effects of the CML myeloid cell cytoplasmic protein on the electrophoretic mobility of nuclear protein-DNA complexes. These data suggest that a unique phosphatase may be involved in the abnormalities in CML which are modulated by interferon-alpha.
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PMID:A phosphatase activity present in peripheral blood myeloid cells of chronic myelogenous leukemia patients but not normal individuals alters nuclear protein binding to transcriptional enhancers of interferon-inducible genes. 224 38

Human myeloid cell nuclear differentiating antigen (MNDA) is a Mr 55,000 non-histone basic nuclear protein expressed in myeloid leukemia cell lines that are at late stages of differentiation (HL-60 and U937) and in normal granulocytes and monocytes, but is not present in lymphoid cells or in other human cells and tissues tested. Affinity purified monospecific polyclonal antibodies and rat monoclonal antibodies have been developed for the immunocytochemical detection of MNDA. Using these antibodies, we surveyed 21 cases of acute leukemia classified by French-American-British (FAB) Group criteria, two cases of biphenotypic acute leukemia and one case of blast crisis of chronic granulocytic leukemia for the presence of MNDA. The most intense staining reactions were present in the nuclei of two cases of acute promyelocytic (FAB M3) leukemia. MNDA was not detected in three of five cases of acute myeloblastic leukemia without maturation (FAB M1). The remaining two cases of the M1 category showed weak to moderate staining. No staining reaction was seen in acute lymphocytic leukemia (ALL), biphenotypic leukemia or the lymphoid blast crisis of chronic granulocytic leukemia. Variable staining reactions were demonstrated in the remaining cases. These data suggest that the presence of MNDA is correlated with myeloid and monocytic differentiation in acute leukemia, being strongly expressed in M3 type, often not detected in M1 leukemia and absent in ALL.
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PMID:Expression of human myeloid cell nuclear differentiation antigen (MNDA) in acute leukemias. 225 28

Cytoplasmic protein extracts from chronic myelogenous leukemia (CML) cells contained an activity that altered the electrophoretic mobility of complexes formed between nuclear proteins and the transcriptional enhancers of interferon (IFN)-inducible genes. Exposure of CML cells to IFN-alpha diminished the effect of the CML cytoplasmic proteins on these nuclear protein-DNA complexes. The presence of clinical responsiveness to IFN-alpha correlated with the sensitivity to the IFN-induced change in the electrophoretic mobility of nuclear protein-DNA complexes. These data suggest that the action of IFN-alpha in CML may be linked to a pathway that can result in posttranslational modification of nuclear proteins.
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PMID:Interferon affects nuclear proteins in cells of clinically sensitive chronic myelogenous leukemia patients. 240 Aug 7

Molecular mechanisms responsible for the clinical progression of chronic myelocytic leukemia to its accelerated phase or to blast crisis have not been defined. We found alterations of the p53 gene (p53 is a 53-kDa nuclear protein) including deletions and rearrangements in 8 of 34 patients in blast crisis and 1 of 4 patients in the accelerated phase, but in only 1 of 38 patients in the chronic phase of chronic myelocytic leukemia. Only two other examples of p53 gene alterations were found among 203 patients with hematologic malignancies and solid tumors. Transcripts of the p53 gene were uniformly found in chronic-phase cells, but gene expression was variable in blast crisis, and transcripts were reduced or undetectable in 10 of 16 patients. Heterogeneous alterations in the structure and expression of the p53 gene appear to be relatively frequent in blast crisis and may be involved in the evolution of disease.
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PMID:Alterations in the p53 gene and the clonal evolution of the blast crisis of chronic myelocytic leukemia. 277 57

The p53 is a nuclear protein that is associated with normal cellular proliferation and can cooperate with Ha-ras in causing cellular transformation in vitro. Lineage association is known to exist between p53 expression and normal lymphopoiesis, but not myelopoiesis. We studied the expression of p53 using chronic myelogenous leukemia (CML) cell lines, somatic hybrids of these cells, and leukemic cells from CML patients. Lymphoid CML lines expressed both p53 mRNA and protein. We also analyzed p53 synthesis by two B-lymphoid lines from the same CML patient; cells of one line were derived from the neoplastic clone, cells of the other were derived from the normal clone. Both synthesized equal amounts of a phosphorylated p53 protein. None of the myeloid CML lines expressed detectable p53 protein and two of four expressed negligible p53 mRNA. Two other myeloid CML lines and myeloid cells from three of four patients expressed p53 mRNA. These findings suggest that expression of the gene is not regulated normally in CML. Several approaches were pursued to explore the differential expression of p53. Southern blot analyses showed no gross alterations in the p53 gene from cells of either the expressing or the nonexpressing lines. No difference in the pattern of demethylated CpG sites was noted in the region of the p53 gene in cells from K562 (myeloid p53 nonexpressor) and in BV173 (lymphoid p53 expressor). The sites of demethylation clustered in and around the p53 promoter in both cell lines. Somatic hybrids formed between a p53 mRNA nonexpressor myeloid line (K562) and the parental p53 expressor lymphoid lines (Daudi, PUT) produced p53 mRNA and protein, suggesting that p53 is a dominantly expressed protein and that lack of expression in myeloid cells is not mediated by a trans-acting negative regulatory protein. DNA transfection experiments performed using the indicator gene chloramphenicol acetyltransferase attached to promoter sequences of p53 showed that these constructs were equally activated in BV173 (p53 expressor) and K562 (p53 mRNA nonexpressor). The mechanism of p53 regulation in CML remains unclear.
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PMID:p53 in chronic myelogenous leukemia. Study of mechanisms of differential expression. 328 Jul 26

Terminal deoxynucleotidyl transferase (TdT) is a nuclear protein widely used as a marker for the diagnosis and classification of acute leukemia. The usual methods for detecting TdT require smears, imprints, or cryostat sections of unfixed tissue. A polyclonal rabbit anti-TdT serum was used to immunostain 54 routinely processed bone marrow sections from patients with acute leukemic disorders, using a recently described antigen-unmasking technique based on microwave oven heating. The specificity of this method of TdT analysis was confirmed by comparing the results obtained with conventional TdT analysis by indirect immunofluorescence. Terminal deoxynucleotidyl transferase reactivity was also evaluated in 44 nonmalignant and normal bone marrow specimens. All cases that were TdT-positive by immunofluorescence (41 of 42 "pre-B" and T-cell acute lymphoblastic leukemia, 2 of 5 acute myeloid leukemia, and 1 of 5 chronic myeloid leukemia in blast crisis) were also positive in paraffin sections. The percentage fluorescence positivity correlated with the percentage of immunoperoxidase stained cells in 44 of 45 cases. The remaining nonneoplastic and normal bone marrow biopsy specimens were TdT-negative. These results show that TdT immunoperoxidase staining of conventionally processed bone marrow specimens can be readily achieved by the use of a simple antigen-unmasking technique and may provide useful diagnostic information particularly in cases in which fresh tissue samples are unavailable.
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PMID:Terminal deoxynucleotidyl transferase staining in acute leukemia and normal bone marrow in routinely processed paraffin sections. 752 7

In the 8;21 translocation, the AML1 gene, located at chromosome band 21q22, is translocated to chromosome 8 (q22), where it is fused to the ETO gene and transcribed as a chimeric gene. AML1 is the human homolog of the recently cloned mouse gene pebp2 alpha B, homologous to the DNA binding alpha subunit of the polyoma enhancer factor pebp2. AML1 is also involved in a translocation with chromosome 3 that is seen in patients with therapy-related acute myeloid leukemia and myelodysplastic syndrome and in chronic myelogenous leukemia in blast crisis. We have isolated a fusion cDNA clone from a t(3;21) library derived from a patient with therapy-related myelodysplastic syndrome; this clone contains sequences from AML1 and from EAP, which we have now localized to band 3q26. EAP has previously been characterized as a highly expressed small nuclear protein of 128 residues (EBER 1) associated with Epstein-Barr virus small RNA. The fusion clone contains the DNA binding 5' part of AML1 that is fused to ETO in the t(8;21) and, in addition, at least one other exon. The translocation replaces the last nine codons of AML1 with the last 96 codons of EAP. The fusion does not maintain the correct reading frame of EAP and may not lead to a functional chimeric protein.
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PMID:The 3;21 translocation in myelodysplasia results in a fusion transcript between the AML1 gene and the gene for EAP, a highly conserved protein associated with the Epstein-Barr virus small RNA EBER 1. 839 54

We investigated the effect of gamma-interferon (gamma-IFN) on three cellular parameters: cell membrane fluidity and expression of two antigens that have been associated with cell proliferation, namely transferrin receptor (Tf-R: a cell surface protein) and Ki-67 antigen (Ki-67: a nuclear protein). We observed small, yet significant changes in the first two parameters, but not the third parameter. These were investigated in K562 cells, a human chronic myelocytic leukemia cell line. These results suggest that the microviscosity changes and the surface Tf-R density were closely associated, and that gamma-IFN was involved in increasing proliferative activity of the cells by decreasing membrane fluidity and upregulating Tf-R expression.
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PMID:Gamma-interferon upregulates transferrin receptors and decreases membrane microviscosity in K562 cells. 877 72

In order to determine new signal transduction pathways implicated in chronic myeloid leukaemia (CML), we performed a gene expression profile comparison between CD34+ cells from CML patients and healthy donors. Functional studies were performed using the Mo7e and Mo7e-p210 cell lines. Expression of CCND1 (Cyclin D1), as well as the chaperone HSPA8, which is important for regulation of CCND1, were significantly upregulated in CD34+ CML cells. Upregulation of HSPA8 was dependent, at least in part, on STAT5 (signal transducer and activator of transcrition 5)-dependent transcriptional activation, as demonstrated by chromatin immunoprecipitation. The presence of HSPA8 in the nuclear protein fraction as well as its binding to CCND1 suggests that it may contribute to stabilization of the CCND1/CDK4 complex, which, in turn, may participate in proliferation of CML cells. Treatment of CML cells with the specific HSPA8 inhibitor 15-deoxyspergualin induced inhibition of CML cell viability but did not induce apoptosis. In conclusion, our studies suggest that STAT5-mediated activation of HSPA8 induces nuclear translocation and activation of the CCND1/CDK4 complex leading to increased proliferation of CML cells, deciphering a new pathway implicated in CML and supporting a potential role of chaperone inhibitors in the treatment of CML.
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PMID:BCR-ABL1-induced expression of HSPA8 promotes cell survival in chronic myeloid leukaemia. 1853 72


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