Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0023418 (leukemia)
 93,477 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The long terminal repeat of Moloney murine leukemia virus (MuLV) contains the upstream conserved region (UCR). The UCR core sequence, CGCCATTTT, binds a ubiquitous nuclear factor and mediates negative regulation of MuLV promoter activity. We have isolated murine cDNA clones encoding a protein, referred to as UCRBP, that binds specifically to the UCR core sequence. Gel mobility shift assays demonstrate that the UCRBP fusion protein expressed in bacteria binds the UCR core with specificity identical to that of the UCR-binding factor in the nucleus of murine and human cells. Analysis of full-length UCRBP cDNA reveals that it has a putative zinc finger domain composed of four C2H2 zinc fingers of the GLI subgroup and an N-terminal region containing alternating charges, including a stretch of 12 histidine residues. The 2.4-kb UCRBP message is expressed in all cell lines examined (teratocarcinoma, B- and T-cell, macrophage, fibroblast, and myocyte), consistent with the ubiquitous expression of the UCR-binding factor. Transient transfection of an expressible UCRBP cDNA into fibroblasts results in down-regulation of MuLV promoter activity, in agreement with previous functional analysis of the UCR. Recently three groups have independently isolated human and mouse UCRBP. These studies show that UCRBP binds to various target motifs that are distinct from the UCR motif: the adeno-associated virus P5 promoter and elements in the immunoglobulin light- and heavy-chain genes, as well as elements in ribosomal protein genes. These results indicate that UCRBP has unusually diverse DNA-binding specificity and as such is likely to regulate expression of many different genes.
 ...
PMID:Cloning of a negative transcription factor that binds to the upstream conserved region of Moloney murine leukemia virus. 130 93

The immediate-early response gene, EGR-1, encodes a zinc finger-containing transcription factor that is involved in growth and differentiation of a variety of cell types. EGR-1 is induced in normal T cells following mitogenic stimulation and has recently been shown to be constitutively expressed in human T-cell leukemia virus type I (HTLV-I)- and type II (HTLV-II)-transformed T-cell lines. The trans-activating protein of HTLV-I, Tax, has been demonstrated to trans-activate promoters of a number of cellular genes, some of which may be critical in regulating T-cell proliferation. In this study, we examine the effect of Tax on expression of EGR-1 in three T-cell lines and demonstrate that both HTLV-I and -II Tax are capable of trans-activating human EGR-1 recombinant promoter constructs. Interestingly, HTLV-I and -II Tax trans-activate the human EGR-1 promoter through different promoter regions in the Jurkat cell line, suggesting that HTLV-I and -II Tax may lead to constitutive expression of EGR-1 through different signaling pathways. Deregulated expression of EGR-1 may contribute to uncontrolled cell growth and transformation during early stages of T-cell activation in HTLV-I and -II-infected cells.
 ...
PMID:HTLV-I and HTLV-II tax trans-activate the human EGR-1 promoter through different cis-acting sequences. 135 92

ELP, the embryonal LTR binding protein, is a member of the nuclear receptor superfamily and a mouse homologue of Drosophila FTZ-F1. ELP is expressed specifically in undifferentiated mouse embryonal carcinoma cells and participates in suppression of the Moloney murine leukemia virus genome. The zinc finger domain of the protein was fused with glutathione S-transferase and was successfully used for isolating genomic targets. Sixteen genomic fragments were isolated and twelve of them strongly interacted with ELP. Six of the ELP binding fragments were analyzed further. All of these contained the multiple binding sites for ELP, which matched well with the consensus binding sequence for FTZ-F1, YCAAGGYCR. Among these, three fragments functioned as negative regulatory elements in response to ELP, when placed upstream to the promoter region of the Moloney leukemia virus. These results indicate that ELP may function as a negative transcription factor for a variety of cellular sequences, in addition to suppressing expression of Moloney leukemia virus in early embryonal cells. It was also shown that the procedure employed here works well for isolation of genomic targets of transcription factors.
 ...
PMID:Isolation of high affinity cellular targets of the embryonal LTR binding protein, an undifferentiated embryonal carcinoma cell-specific repressor of Moloney leukemia virus. 157 38

The core of retroviruses contains a highly conserved, low molecular weight, basic protein that binds nucleic acids and is essential for genomic RNA packaging. The 56 amino acid protein, NCp10, of Moloney Murine Leukaemia virus (MoMuLV) has the CysX2 CysX4 HisX4 Cys zinc finger-like motif shared by all retrovirus nucleocapsid proteins. The native protein and five modified peptides containing the zinc binding domain were synthesized by solid phase in order to investigate the structural and biochemical role of Zn2+ chelation in MoMuLV NCp10 activity. The purity of the synthetic molecules was verified by HPLC and their sequences were confirmed by amino acid analysis and sequencing in the case of NCp10. Thiol dosage agreed with the theoretical value of free cysteine for all these molecules. Fluorescence measurements performed on synthetic NCp10 and zinc finger fragments showed that the tryptophan quantum yield was Zn2(+)-dependent, allowing a 1:1 stoichiometry for the complex to be determined. The apparent affinity constant of NCp10 for the metal was estimated to be superior to 10(6) M-1. The synthetic protein, in the presence of Zn2+ ions, possesses all the biological properties of NCp10 isolated from virions. It catalyzes both the MoMuLV RNA dimerization and the annealing of the replication primer tRNA(Pro) onto MoMuLV RNA.
 ...
PMID:Solid phase synthesis of the retroviral nucleocapsid protein NCp10 of Moloney murine leukaemia virus and related "zinc-fingers" in free SH forms. Influence of zinc chelation on structural and biochemical properties. 170 45

Human immunodeficiency virus type 1 (HIV-1) and human T-cell leukemia virus type I (HTLV-I) were purified by sucrose density gradient centrifugation in the presence of 1 mM EDTA. Pelleted gradient fractions were analyzed for total protein, total Gag capsid protein, and total zinc. Zinc was found to copurify and concentrate with the virus particles. Through successive cycles of resuspending in buffer containing EDTA and repelleting, the zinc content remained constant at about 1.7 mol of zinc per mol of Gag protein. Proteins from purified virus (HIV-1 and HTLV-I) were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, blotted to polyvinylidene fluoride paper, and probed with 65ZnCl2. Viral nucleocapsid (NC) proteins (HIV-1 p7NC and HTLV-I p15NC) bound 65Zn2+. Other retroviruses, including simian immunodeficiency virus, equine infectious anemia virus, bovine leukemia virus, Moloney murine leukemia virus, mouse mammary tumor virus, and Mason-Pfizer monkey virus, were found to contain amounts of zinc per milligram of total protein similar to those found in HIV-1 and HTLV-I. Collectively, these data support the hypothesis that retroviral NC proteins function as zinc finger proteins in mature viruses.
 ...
PMID:Tightly bound zinc in human immunodeficiency virus type 1, human T-cell leukemia virus type I, and other retroviruses. 173 Nov 11

To search for genes that can collaborate with myc in lymphomagenesis, we exploited retroviral insertional mutagenesis in E mu-myc transgenic mice. Moloney murine leukemia virus accelerated development of B lymphoid tumors. Three quarters contained a provirus within the known pim-1 or pim-2 loci, new loci bmi-1 and emi-1, or combinations of these. bmi-1 insertions predominated, occurring in half the tumors, and resulted in elevated bmi-1 mRNA levels. Significantly, the bmi-1 gene, which is expressed in diverse normal cells, encodes a Cys/His metal-binding motif (C3HC4) that resembles those in several DNA-binding proteins and defines a new category of zinc finger gene. Thus, myc-induced lymphomagenesis can entail the concerted action of several genes, including the presumptive nuclear regulator bmi-1.
 ...
PMID:Novel zinc finger gene implicated as myc collaborator by retrovirally accelerated lymphomagenesis in E mu-myc transgenic mice. 182 28

Human T-cell leukemia virus type 1 (HTLV-1) is an etiological agent of adult T-cell leukemia (ATL). We showed here by mobility-shift assay that T-cell lines transformed with the virus contained high levels of AP-1 activities. Consistent with this result, these cell lines expressed increased levels of mRNAs encoding the AP-1 proteins, c-Fos, Fra-1, c-Jun, JunB, and JunD. Previously, transcription of the c-fos gene has been reported to be transactivated by the viral transcription factor, Tax1. By using the human T-cell line (JPX-9), in which expression of the Tax1 is inducible, we showed that expression of mRNAs for Fra-1, c-Jun, and JunD was also transactivated by Tax1. Moreover, Tax1 activated expression of two other transcription factors having zinc finger motifs, Egr-1 and Egr-2, in the same cells. The Tax1-inducible transcription factors identified here are encoded by the members of immediate early genes under the control of growth signals. Thus, Tax1 was suggested to replace growth signals, at least in part, by this mechanism.
 ...
PMID:HTLV-1 Tax induces expression of various immediate early serum responsive genes. 190 55

The zinc fingers of retroviral gag nucleocapsid proteins (NC) are required for the specific packaging of the dimeric RNA genome into virions. In vitro, NC proteins activate both dimerization of viral RNA and annealing of the replication primer tRNA onto viral RNA, two reactions necessary for the production of infectious virions. In this study the role of the zinc finger of Moloney murine leukemia virus (MoMuLV) NCp10 in RNA binding and annealing activities was investigated through modification or replacement of residues involved in zinc coordination. These alterations did not affect the ability of NCp10 to bind RNA and promote RNA annealing in vitro, despite a complete loss of zinc affinity. However mutation of two conserved lysine residues adjacent to the finger motif reduced both RNA binding and annealing activities of NCp10. These findings suggest that the complexed NC zinc finger is not directly involved in RNA-protein interactions but more probably in a zinc dependent conformation of NC protein modulating viral protein-protein interactions, essential to the process of viral RNA selection and virion assembly. Then the NC zinc finger may cooperate to select the viral RNA genome to be packaged into virions.
 ...
PMID:Viral RNA annealing activities of the nucleocapsid protein of Moloney murine leukemia virus are zinc independent. 190 2

The murine Evi-1 gene encodes a protein that has multiple 28-amino acid repeats containing the consensus sequence found in the zinc finger domains of many transcriptional regulatory proteins. Activation of the expression of the Evi-1 gene is frequently found in murine myeloid leukemias and leukemia cell lines and is due to retroviral insertions in the 5' region of the gene in either the Evi-1 or the CB-1/FIM3 common sites of viral integrations. To examine the role of the Evi-1 gene in human leukemias we have cloned regions of the human locus corresponding to the coding region of the gene and regions corresponding to the Evi-1 and CB-1/FIM3 common sites of integrations. Using these probes we demonstrate that the human Evi-1 gene maps to chromosome 3q24-q28 in a region that is translocated in acute nonlymphocytic leukemias with a t(3;5)(q25;q34). By in situ hybridization with metaphase chromosomes from one patient with a 3;5 translocation, the Evi-1 gene was found to be translocated to the derivative 5 chromosome. However, no rearrangements were detected by Southern blot analysis with DNAs from three patients with a t(3;5) using probes from the Evi-1 or CB-1/FIM3 loci. No Evi-1 transcripts were detected with RNA from leukemic blasts of one patient with a t(3;5).
 ...
PMID:The human Evi-1 gene is located on chromosome 3q24-q28 but is not rearranged in three cases of acute nonlymphocytic leukemias containing t(3;5)(q25;q34) translocations. 210 5

A monoclonal antibody (MAb) was generated against a synthetic peptide corresponding to amino acids 148 to 163 of the rfp protein with zinc finger domains. The MAb, designated RFP-1 (IgM), which was positive with the immunizing peptide in enzyme-linked immunosorbent assay, was reactive in immunoblotting with an in vitro translated rfp product as well as with native proteins in cell extracts made from mouse testis and HL-60 human leukemia cell line, both of which were previously shown to express high levels of rfp mRNA. When HL-60 cells were fractionated into nuclear and cytoplasmic components, the protein reactive with RFP-1 MAb was detectable only in the nuclear fraction. By the avidin-biotin complex immunoperoxidase method, this MAb strongly stained over 90% of the nuclei of human and mouse spermatogenic cells, except mature spermatozoon, and of human testicular tumor cells. In other human adult tissues, up to 60% of positive cells were observed. These antibody activities were clearly absorbed by pre-incubation of RFP-1 MAb with the immunizing peptide. These results thus indicated that RFP-1 MAb recognizes a nuclear protein which is expressed at high levels in male germ cells.
 ...
PMID:Nuclear localization of antigens detected by a monoclonal antibody against a synthetic peptide of rfp finger protein. 211 13


1 2 3 4 5 6 7 8 9 10 Next >>