Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:2.7.7.49 (reverse transcriptase)
31,746 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

MDR1 gene expression was examined in acute leukemia cells from 75 Japanese patients at diagnosis (50 with acute myeloblastic leukemia [AML]: 10 M1, 18 M2, 5 M3, 8 M4, 9 M5; 25 with acute lymphoblastic leukemia [ALL]: 13 B-precursor, 12 T-lineage). The results of MDR1 mRNA expression by reverse transcriptase polymerase chain reaction were confirmed by immunostaining using the anti-P-glycoprotein monoclonal antibody UIC2 and by a functional study using the rhodamine efflux test. Morphologically, AML M1 cases had the highest incidence of MDR1 gene expression (6 of 10 patients). Phenotypically, CD7 and CD34 were the only surface markers that were significantly associated with MDR1 gene expression (P < .01). In CD7+CD4-CD8- ALL, which is thought to originate from the lymphohematopoietic stem cell, expressed the MDR1 gene with a high incidence (six of eight patients), whereas three surface CD3+ and one CD4+CD8+ T-cell ALL (T-ALL) did not have detectable MDR1 transcripts. Only two cases of 13 B-precursor ALL had MDR1 mRNA, one of which had the Philadelphia (Ph1) chromosome. No association was observed between MDR1 gene expression and CD34 positivity in ALL. Our results that MDR1 mRNA was frequently expressed in CD7+ AML and CD7+CD4-CD8- ALL, together with the previous reports indicating clinical similarities between these leukemias, provides a clue to clarify a relationship between CD7+ AML and CD7+CD4-CD8- ALL. In addition, MDR1 expression in CD7+ AML/ALL might be responsible for the poor response to conventional chemotherapies of these types of leukemia.
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PMID:Expression of MDR1 gene in acute leukemia cells: association with CD7+ acute myeloblastic leukemia/acute lymphoblastic leukemia. 769 87

Inactivation of the deleted in colorectal carcinoma (DCC) tumor suppressor gene has been reported not only in colorectal carcinoma but also in other human malignancies. In order to evaluate the role of the DCC gene in leukemogenesis, we examined DCC expression using the reverse transcriptase-polymerase chain reaction (RT-PCR) method. Expression of the DCC gene was reduced or absent in 10 of 39 (26%) patients with acute myelogenous leukemia (AML), three of 14 (29%) patients with acute lymphocytic leukemia (ALL), seven of 33 (21%) patients with chronic myelogenous leukemia (CML), three of 39 (8%) patients with myelodysplastic syndromes (MDS), and five of nine (56%) patients with overt leukemia progressed from MDS. These findings suggest that inactivation of the DCC gene contributes to some instances of leukemogenesis.
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PMID:Expression of the DCC gene in human hematological malignancies. 769 19

We investigated expression of the human ecotropic virus integration site-1 (EVI1) gene in patients with leukemia and myelodysplastic syndrome (MDS) using the reverse transcriptase-polymerase chain reaction (RT-PCR) method. The EVI1 transcripts were detected in 5 (10.0%) of 50 patients with de novo acute myeloid leukemia (AML), including two AML patients with trilineage myelodysplasia, and in 8 (34.8%) of 23 patients with post-myelodysplastic syndrome AML (post-MDS AML). EVI1 expression was also detected in 6 (35.3%) of 17 MDS patients and three of six patients with chronic myeloid leukemia (CML) in myelomegakaryoblast crisis. No EVI1 transcripts were detected in patients with acute lymphoid leukemia (n = 15) or CML in lymphoid blast crisis (n = 4). Chromosomal abnormalities at the 3q26 region, where the EVI1 gene is located, were found in one patient with MDS and two patients with CML myelomegakaryoblast crisis who had EVI1 expression. Our results showed that EVI1 expression was frequent in patients with post-MDS AML and AML with trilineage myelodysplasia, regardless of the presence or absence of 3q26 abnormalities. EVI1 expression was accompanied by expression of GATA-1 and GATA-2, and often by stem cell leukemia (SCL) gene expression. In patients with post-MDS AML, EVI1 expression was not always associated with a 3q26 abnormality, whereas EVI1 expression in CML myelomegakaryoblast crisis was often linked to a 3q26 abnormality. Our results suggest that the leukemogenic role of EVI1 expression may differ between post-MDS AML and leukemia, with EVI1 expression associated with a 3q26 abnormality.
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PMID:Ecotropic virus integration site-1 gene preferentially expressed in post-myelodysplasia acute myeloid leukemia: possible association with GATA-1, GATA-2, and stem cell leukemia gene expression. 778 Jan 55

As acute nonlymphocytic leukemia (ANLL) with inv(16) (p13q22) or t(16;16)(p13;q22) has been shown to result from the fusion of transcription factor subunit core binding factor (CBFB) to a myosin heavy chain (MYH11), we sought to design methods to detect this rearrangement using reverse transcriptase-polymerase chain reaction (RT-PCR). In all of 27 inv(16)(p13q22) and four t(16;16)(p13;q22) cases tested, a chimeric CBFB-MYH11 transcript coding for an in-frame fusion protein was detected. In a more extensive RT-PCR analysis with different primer pairs, we detected a second new chimeric CBFB-MYH11 transcript in 10 of 11 patients tested. The CBFB-MYH11 reading frame of the second transcript was maintained in one patient but not in the others. We show that the different CBFB-MYH11 transcripts in one patient arise from alternative splicing. Translation of the transcript in which the CBFB-MYH11 reading frame is not maintained leads to a slightly truncated CBFB protein.
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PMID:RT-PCR diagnosis of patients with acute nonlymphocytic leukemia and inv(16)(p13q22) and identification of new alternative splicing in CBFB-MYH11 transcripts. 779 33

The translocation between chromosomes 8 and 21, t(8;21)(q22;q22), is the most frequent abnormality seen in approximately 46% of patients with acute myeloid leukemia with French-America-British (FAB)-M2 morphology and an aneuploid karyotype. The breakpoints in this translocation have been characterized at the molecular level, and the genes involved are AML1 on chromosome 21 and ETO (eight twenty one) on chromosome 8. AML1 has homology to the alpha subunit of the murine polyoma enhancer binding protein, pebp2, and to the segmentation gene, runt, of Drosophila melanogaster. ETO, also called MTG8 (myeloid translocation gene on 8) has no overall homology to known proteins, but it contains two DNA-binding zinc finger motifs and several regions that are proline- and serine-rich. Both AML1 and ETO are thought to be transcription factors because the motifs they contain are found in other transcription factors. Both genes are transcribed from telomere to centromere, and cytogenetic analysis of variant translocations has shown that the critical junction always conserved is on the derivative 8 chromosome. The rearrangement between the two chromosomes results in a fusion gene that contains the 5' region of AML1 including that homologous to runt fused to almost all of ETO. The fusion transcript from the der(8) chromosome is consistently detected in patients with the t(8;21). The translocation can be detected at the molecular level with selected genomic DNA probes from chromosome 21 and from chromosome 8 near the breakpoint in 80-100% of the t(8;21) patients at diagnosis and in relapse, and with reverse transcriptase-polymerase chain reaction (RT-PCR) in all of the patients at diagnosis and in long-term remission. These results indicate that leukemic clones are still circulating in patients who have been in remission for as long as 8 years.
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PMID:The AML1 and ETO genes in acute myeloid leukemia with a t(8;21). 781 94

Expression patterns of interleukin-6 (IL-6), IL-6 receptor (IL-6R), and gp130 genes in 39 patients with acute myeloid leukemia (AML), in 23 patients with acute lymphoblastic leukemia (ALL), and in 7 patients with acute mixed lineage leukemia (AMLL) were studied by quantitative reverse transcriptase-polymerase chain reaction. Significant levels of IL-6 were expressed in 8 (21%) of 39 AML patients and in 2 (29%) of 7 AMLL patients, whereas in ALL, the expression of IL-6 was almost negligible. IL-6R was expressed in all patients with AML and AMLL, whereas only half of ALL patients expressed low levels of IL-6R as compared with those with AML and AMLL. However, gp130 was ubiquitously expressed in all the leukemia patients, and there was no significant difference in gp130 expression among AML, ALL, and AMLL. Significant correlation was observed between the expression of IL-6R and gp130 in AML. When tested for in vitro response to IL-6, the leukemic cells from 3 of 7 AML, none of 3 ALL, and both of 2 AMLL patients significantly responded to IL-6, showing the correlation between the expression levels of IL-6R and gp130 and the responsiveness of leukemic cells to IL-6. These results showed that quantitation of IL-6R and gp130 expression by reverse transcriptase-polymerase chain reaction is useful for the rapid prediction of the responsiveness of leukemic cells to IL-6, especially in cases of administration of IL-6.
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PMID:Expression of the interleukin-6 (IL-6), IL-6 receptor, and gp130 genes in acute leukemia. 791 80

Seven patients with acute myeloid leukaemia (AML) type M2 and t(8;21), treated with intensive chemotherapy followed in two cases by allogeneic or autologous bone marrow transplant (BMT), were tested for the presence of transcripts of the characteristic chimaeric gene AML1/ETO by reverse transcriptase polymerase chain reaction (RT-PCR) at serial intervals during remission. Six patients, including both BMT patients, demonstrated persistence of t(8;21), one being consistently negative in peripheral blood but bone marrow positive. Bone marrow may, therefore, be more reliable than peripheral blood for detecting residual t(8;21) cells. Our results show persistence of t(8;21) cells in AML-M2 patients following chemotherapy or BMT, some of whom were in long-term remission.
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PMID:Detection of t(8;21) by reverse transcriptase polymerase chain reaction in patients in remission of acute myeloid leukaemia type M2 after chemotherapy or bone marrow transplantation. 799 71

Pericentric inversion of chromosome 16 [inv(16)(p13q22)] and the related t(16;16)(p13;q22) are seen in a subset of acute myelogenous leukemia (AML) phenotypically and prognostically differing from other cases. We have recently shown that inv(16) results in fusion of CBFB/PEBP2B, a gene encoded at 16q22 to MYH11, a smooth muscle myosin heavy chain gene encoded at 16p13. Chimeric transcripts consisting of upstream CBFB fused to downstream MYH11 coding sequences result from this fusion. In this study we have examined a series of 37 of these cases using reverse transcriptase-polymerase chain reaction (RT-PCR) to detect expression of a hybrid CBFB/MYH11 transcript. Chimeric cDNAs were detected in all but 1 of 37 leukemias with typical inv(16) or t(16;16). Such chimeric products were not seen in a case with inv(16)(p13q24) (ie, a variant q arm breakpoint) or any of 10 cases of AML without these chromosomal changes. Four different chimeric transcripts were found, representing differing fusion points within MYH11 spliced to position 495 of CBFB. Primer sets are described for efficient amplification of these different cDNA forms. Amplification of cDNA showed that all but 17 codons of the CBFB coding sequence are included in the abnormal transcripts. RT-PCR was shown to be highly sensitive and potentially useful for detection of leukemic cells during morphologic remission.
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PMID:Detection of fusion transcripts generated by the inversion 16 chromosome in acute myelogenous leukemia. 814 42

Previous studies have demonstrated the expression of GATA-1 (a DNA-binding nuclear protein) in erythrocytes, megakaryocytes, eosinophils, basophils, mast cells, early marrow progenitor cells and in mouse and human erythroid leukaemia cell lines. We studied 31 bone marrow specimens from patients with acute myeloid leukaemia (AML) for GATA-1 expression by reverse transcriptase/polymerase chain reaction (RT/PCR) analysis. GATA-1 expression was detected in all of the patients with erythroleukaemia, and in one of nine patients with megakaryoblastic leukaemia, but absent from 17 patients with French-American-British (FAB) M1-5 leukaemia. In AML, GATA-1 expression is indicative of differentiation to the erythroid and possibly megakaryocytic lineages, analogous to its expression in normal haemopoiesis.
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PMID:GATA-1 is expressed in acute erythroblastic leukaemia. 819 39

Acute promyelocytic leukemia (APL) is a rare subtype of acute myelogenous leukemia. It is frequently associated with a life-threatening hemorrhagic diathesis, often aggravated by induction cytotoxic chemotherapy. Patients with APL have bone marrow infiltration by abnormal promyelocytes, usually with prominent cytoplasmic granulation. These patients have a unique cytogenetic abnormality, a balanced reciprocal translocation between the long arms of chromosomes 15 and 17. The nuclear retinoic acid receptor alpha gene, on chromosome 17, is translocated to the PML gene region, on chromosome 15, resulting in the synthesis of two fusion messenger ribonucleic acids, PML/RAR-alpha and RAR-alpha/PML, easily detected by the reverse transcriptase polymerase chain reaction. This assay is extremely useful in the diagnosis and detection of minimal residual disease in APL patients. All trans-retinoic acid (ATR) differentiates the malignant cell clone and corrects the coagulopathy associated with this disease. The most important adverse effect is a respiratory distress syndrome, treatable with steroids, if detected at its onset. ATR yields durable remissions in patients with APL, after consolidation with cytotoxic chemotherapy.
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PMID:[Acute promyelocytic leukemia. The therapeutic advances]. 828 19


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