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)

Two new myeloid cell lines (K051 and K052) were established from a patient with multilineage CD7-positive acute leukemia. The K051 and K052 were established from the patient's bone marrow cells at diagnosis and at relapse, respectively. The K051 cell expressed myeloid-associated antigens (CD13 and CD33), a platelet-associated antigen (CD41), and an erythroid antigen (glycophorin A). The K052 cell expressed myeloid-associated antigens (CD13, CD14, and CD33), lymphoid markers (CD2, CD5, and CD7), and HLA-DR. Chromosome analysis of both cell lines showed a 17p- chromosome. Both cell lines were investigated for aberrations of the p53 gene and the N-ras gene. A p53 mutation detected in both cell lines consisted of a C-->T substitution in codon 248. An N-ras mutation detected only in the K052 cell consisted of a G-->C substitution in codon 13. Expression of the multidrug resistance gene (MDR1) was also investigated by the semiquantitative reverse transcriptase-polymerase chain reaction (RT-PCR). MDR1-mRNA was more highly expressed by the K052 cell than the K051 cell, being equivalent to that in HEL cells. The functional MDR1-protein against vincristine was also observed, and its function was inhibited by verapamile and Cyclosporin A. The K052 cells were capable of phenotypic or morphologic differentiation after being incubated with granulocyte colony-stimulating factor, interleukin-2, phorbol 12-myristate 13-acetate, or 1,25-dihydroxy-vitamin D3. In contrast, the K051 cells responded phenotypically to retinoic acid. Thus, the K051 and K052 cell lines will be useful for investigating the cellular and molecular events in leukemogenesis and differentiation, and the mechanism of expression of the MDR1 gene.
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PMID:p53 and N-ras mutations in two new leukemia cell lines established from a patient with multilineage CD7-positive acute leukemia. 769 50

Expression of antigens coexpressed on cord blood (CB) CD34+ cells was evaluated by flow cytometry analysis and reverse transcriptase polymerase chain reaction (RT-PCR). Antigen expression was also comparatively analyzed by flow cytometry and limiting dilution (LD) RT-PCR to investigate effects of chymopapain on epitopes of several cell surface markers: LD RT-PCR allows detection of the expression of antigens degraded by chymopapain which are not identified by flow cytometry. Monoclonal antibodies (MoAbs) that recognize chymopapain resistant epitopes on several coexpressed cell surface markers were identified: these included MoAbs directed against CD11a, CD13, CD18, CD38, CD45RO, CD51, HLA-DR, Thy-1, c-kit, flt-3 (STK-1), and mdr-1. Interestingly, chymopapain treatment caused enhanced staining with MoAbs against HLA-DR, Thy-1, flt-3, mdr-1, and CD51. The frequency (LD RT-PCR) of CD18, CD38, Thy-1, and c-kit RT-PCR signals on pure sorted CD34+ CD18-, CD34+ CD38-, CD34+ Thy-1-, and CD34+ c-kit- cells, respectively, was similar in corresponding subsets treated or not with chymopapain. In contrast, the frequency of CD33 RT-PCR signals on sorted CD34+ CD33- cells was higher in chymopapain-treated samples than in untreated samples and thus confirmed at the transcriptional level that the epitope recognized by anti-CD33 is chymopapain sensitive. Our findings extend data on the phenotypic profile of CB CD34+ cells and show that several key cell surface markers of hematopoietic progenitor cells are chymopapain resistant. In addition, the results of the present study demonstrate that the RT-PCR can be applied to the analysis of multiple RNA species in small numbers of hematopoietic progenitor cells and show that LD RT-PCR allows the identification and frequency determination of rare cells which are undetectable by flow cytometry.
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PMID:Surface antigen expression on CD34+ cord blood cells: comparative analysis by flow cytometry and limiting dilution (LD) RT-PCR of chymopapain-treated or untreated cells. 887 54

We constructed a retroviral vector, pLhIL-9RSN, containing CDNA encoding the human interleukin-9 receptor (IL-9R) along with a neomycin phosphotransferase gene (Neo). In order to study the biological effects of the IL-9R, high titer (1-5 x 10(5) CFU/ml) viral supernatant, generated from the packaging cell lines, ecotropic GPE86 and amphotropic PA317, was used to transduce the IL-9R gene into sorted populations of CD34++ CD33-cells from human cord blood which are highly enriched for erythroid progenitor cells (BFU-E). Colony formation by BFU-E transduced with the IL-9R gene and grown without selection in G418 and in the presence of erythropoietin (Epo) and interleukin (IL)-9 was significantly increased up to three-fold and the size of the erythroid colonies was significantly increased 50-100% compared to colony formation by mock virus transduced cells. Moreover, colony formation by IL-9R-transduced cells was more sensitive to stimulation with lower doses of IL-9 and Epo. Individual colonies formed with or without selection in G418 were evaluated. Proviral integration and mRNA expression were respectively assessed by polymerase chain reaction (PCR) and reverse transcriptase (RT) PCR analysis and were apparent in 93% and 84% of the G418-resistant colonies and 52% and 48% of the colonies grown in the absence of G418. Our study demonstrates that a functional human IL-9R gene can be efficiently transduced into human cord blood hematopoietic progenitors using retroviral vectors with increased cytokine-dependent erythroid colony formation.
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PMID:Transduction of human interleukin-9 receptor gene into human cord blood erythroid progenitors increases the number of erythropoietin-dependent erythroid colonies. 897 79

Although acute myeloid leukemias (AMLs) cytochemically negative for myeloperoxidase are now well recognized, myeloid surface antigen-negative AMLs are rare. The morphologic, cytochemical, immunologic, and cytogenetic or molecular features of such cases are described in four adults aged 19 to 60 years. All had AML with maturation (FAB M2) and were myeloperoxidase positive. Immunologic studies showed all to be HLA-DR positive but negative for the CD13, CD14, and CD33 antigens. Two of four were CD34 antigen positive. Cytogenetic studies were performed in three patients, and all demonstrated t(8;21)(q22;q22). In studies using the reverse transcriptase polymerase chain reaction in two patients, including the patient in whom karytypic analysis was not performed, the AML1-ETO fusion product of t(8;21) was identified. These findings suggest an association between the lack of myeloid antigen expression in myeloperoxidase-positive AML and the presence of t(8;21). In addition, the results demonstrate the continued need for cytochemical studies in the evaluation of acute leukemias.
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PMID:Presence of t(8;21)(q22;q22) in myeloperoxidase-positive, myeloid surface antigen-negative acute myeloid leukemia. 1176 84

To clarify whether the expression of the WT1 gene in leukemic cells is aberrant or merely reflects that in normal counterparts, the expression levels of the WT1 gene were quantitated for normal hematopoietic progenitor cells. Bone marrow (BM) and umbilical cord blood (CB) cells were fluorescence-activated cell sorting (FACS)-sorted into CD34+ and CD34- cell populations, and the CD34+ cells into nine subsets (CD34+ CD33-, CD34+ CD33+, CD34+ CD38-, CD34+ CD38+, CD34+ HLA-DR-, CD34+ HLA-DR+, CD34+ c-kit(high), CD34+ c-kit(low), and CD34+ c-kit-) according to the expression levels of CD34, CD33, CD38, HLA-DR, and c-kit. Moreover, acute myeloid leukemic cells were also FACS-sorted into four populations (CD34+ CD33-, CD34+ CD33+, CD34- CD33+, and CD34- CD33-). FACS-sorted normal hematopoietic progenitor and leukemic cells and FACS-unsorted leukemic cells were examined for the WT1 expression by quantitative reverse transcriptase-polymerase chain reaction. The WT1 expression in the CD34+ and CD34- cell populations and in the nine CD34+ subsets of BM and CB was at either very low (1.0 to 2.4 x 10(-2)) or undetectable (< 10(-2)) levels (the WT1 expression level of K562 cells was defined as 1.0), whereas the average levels of WT1 expression in FACS-sorted and -unsorted leukemic cells were 2.4 to 9.3 x 10(-1). Thus, the WT1 expression levels in normal hematopoietic progenitor cells were at least 10 times less than those in leukemic cells. Therefore, we could not find any normal counterparts of BM or CB that expressed the WT1 at levels comparable with those in leukemic cells. These results indicate an aberrant overexpression of the WT1 gene in leukemic cells and imply the involvement of this gene in human leukemogenesis.
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PMID:Aberrant overexpression of the Wilms tumor gene (WT1) in human leukemia. 902 64

The t(16;21)(p11;q22) translocation is a non-random chromosomal aberration observed in several types of human acute myeloblastic leukemia (AML), whereas the der(16)t(1;16) and chromosome rearrangements at 12q13 are frequently found in solid tumors. A novel cell line YNH-1 was established from peripheral blood cells of a 46-year-old male with AML (M1) carrying t(16;21) and t(1;16) translocations. YNH-1 has been maintained with a doubling time of 82 h for more than 20 months as a granulocyte colony-stimulating factor (G-CSF), granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin-3 (IL-3) dependent line. Morphologically YNH-1 cells were free-floating immature myeloblasts with lobulated nuclei and vacuoles in the cytoplasm. They were positive for myeloperoxidase but negative for alpha-naphthyl butylate esterase and chloroacetate esterase stainings. In surface marker analysis YNH-1 cells were positive for CD13, CD33 and CD34. Chromosomal analysis showed 46, XY, der(16)t(16;21)(p11;q22)t(1;16) (q12;q13), der(21)t(16;21)(p11;q22), der (6)t(6;12)(q13;q13), der(12)t(6;12)(q21;q13). These translocations were confirmed by fluorescence in situ hybridization (FISH) studies with the ERG-YAC clone and chromosome-specific DNA libraries. Both the FUS/ERG and ERG/FUS chimeric transcripts were identified by reverse transcriptase-polymerase chain reaction (RT-PCR) analysis. Thus, YNH-1 could be a useful tool for elucidating the pathophysiology and molecular mechanism in AML with t(16;21),t(1;16) and 12q13 translocations.
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PMID:Establishment of a novel human acute myeloblastic leukemia cell line (YNH-1) with t(16;21), t(1;16) and 12q13 translocations. 909 2

The Wilms' tumor gene (wt1) is strongly expressed in malignant blasts of acute myeloid leukemia (AML) in approximately 80% of all cases. However, the role of wt1 expression in non malignant hematopoietic cells remains unclear. To characterize the expression of wt1 in differentiating hematopoietic progenitors, we isolated and cultured CD34+ progenitor cells from four healthy bone marrow donors with stem cell factor (SCF) and granulocyte colony stimulating-factor (G-CSF) to induce differentiation into granulocytes. Four different cultures were carried out for 12 days. During culture, wt1 mRNA expression was analyzed by defining its ratio relative to beta-actin using reverse transcriptase polymerase chain reaction (RT-PCR). To monitor the stage of differentiation, expression of cell surface markers and peroxidase was analyzed daily. The initial purity of CD34+ cells ranged between 80% and 90%; after 12 days, the frequency of neutrophil bands and segmented neutrophils was approximately 60%. Using RT-PCR to determine the ratio of wt1 to beta-actin expression, we reproducibly detected maximum expression of wt1 mRNA at day 0 in two cultures and at day 1 in two other CD34+ cell cultures; at both these time points nearly all cells fulfilled the morphological and immunephenotypical criteria of early hematopoietic blast cells. Wt1 expression dropped rapidly at day 1 and 2, respectively, in these two pairs of cultures, and was accompanied by an increase of cells expressing CD33 surface antigen. Our data suggest that wt1 expression is restricted to a subset of CD34+ progenitors and downregulated in later stages of differentiation in vitro.
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PMID:The Wilms' tumor gene is expressed in a subset of CD34+ progenitors and downregulated early in the course of differentiation in vitro. 925 7

A 68 year-old-man was first found to have CLL with IgG, kappa monoclonal gammopathy 6 years ago. Bestrabucil (total dose 35,150 mg) was taken orally from August 1989 to December 1989. Etoposide (total dose 23,100 mg) was then orally administered from January 1990 to December 1995. He was then referred to our hospital in January 1996 because of progressive anemia and thrombocytopenia. Peripheral blood showed a WBC of 21,200/microliter with 4% myeloblasts and 79% lymphocytes, Hb 7.9 g/dl and Plt 5 x 10(4)/microliter. The serum level of lysozyme was increased (75.6 micrograms/ml). Bone marrow aspiration disclosed hyper-cellularity with proliferation of the blasts and a monocytoid cell population, which cytochemical studies demonstrated to be of the myelo-monocytic series, thus indicating acute myelogenous leukemia (AML-M4) superimposed on CLL. Surface marker analysis of bone marrow mononuclear cells revealed reactivity for CD 11c, CD13, CD15, CD33, HLA-DR. The karyotype was normal. Southern blot analysis and reverse transcriptase-polymerase chain reaction did not reveal rearrangement of the MLL gene. Complete remission was achieved by chemotherapy consisted of BHAC, idarubicine, 6MP, vincristine and predonisolone. Long-term treatment with oral etoposide may contribute to secondary AML.
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PMID:[Acute myelogenous leukemia (M4) occurring during chronic lymphocytic leukemia]. 942 40

A 48-year-old patient was admitted to our hospital for leukocytosis. The blast cells were positive for peroxidase and he was tentatively diagnosed as acute myeloid leukemia according to the French-American-British criteria. By flow cytometry, the bone marrow cells were positive for CD10, CD13, CD33 and HLA-DR, but two-color analysis revealed that most of the CD13- and CD33-positive cells did not express CD10. The marrow cells had Philadelphia chromosome with no additional abnormalities. Major bcr-abl fusion gene was observed by the reverse transcriptase-polymerase chain reaction method. Southern blot analysis disclosed rearrangement of both immunoglobulin heavy chain and T-cell receptor beta chain genes. He received combined chemotherapy for myeloid lineage and lymphoid lineage, but the response was quite poor. He died 64 days after admission due to pulmonary bleeding. Although the association of Ph1 with multilineage differentiation is unclear, our case has significant implication for further investigation of the relationship between Ph1-positive cells and lineage selection.
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PMID:Dual rearrangement of immunoglobulin and T-cell receptor genes in a case of Philadelphia chromosome-positive acute leukemia. 973 Jan 56

cDNA subtraction was employed to uncover differences in gene expression between myeloproliferative polycythaemia vera (PV) and normal haematopoietic precursors. Following cDNA subtraction using mRNAs isolated from PV and normal CD34+/CD33- bone-marrow cells, expression of the tumour suppressor H19 was found to be low or absent in the PV sample. Low levels of H19 expression in PV patients were confirmed by in situ hybridization. Using semi-quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) to examine expression in the pluripotent haematopoietic cell line FDCP-mix and single bone-marrow precursors, unambiguous IGF2 and H19 expression was demonstrated in normal haematopoietic precursors. Examination of individual bone-marrow precursors revealed that all IGF2-expressing haematopoietic precursors also co-expressed H19, indicating that H19 and IGF2 may be co-ordinately regulated during haematopoiesis. Analysis of FDCP-mix undergoing differentiation and single pluripotent and committed bone-marrow precursors revealed that the pattern of H19 expression coincided with the commitment to a single lineage. Taken together, these observations demonstrate that H19 and IGF2 are specifically expressed during haematopoiesis and that low levels of H19 expression are associated with PV and may contribute to the pathology of the disease.
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PMID:Expression of the imprinted tumour-suppressor gene H19 is tightly regulated during normal haematopoiesis and is reduced in haematopoietic precursors of patients with the myeloproliferative disease polycythaemia vera. 1064 Sep 93


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