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Query: UMLS:C0023418 (leukemia)
 93,477 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Expression of Hoxa7 and Hoxa9 is activated by proviral integration in BXH2 murine myeloid leukaemias. This result, combined with the mapping of the HOXA locus to human chromosome 7p15, suggested that one of the HOXA genes might be involved in the t(7;11)(p15;p15) translocation found in some human myeloid leukaemia patients. Here we show that in three patients with t(7;11), the chromosome rearrangement creates a genomic fusion between the HOXA9 gene and the nucleoporin gene NUP98 on chromosome 11p15. The translocation produces an invariant chimaeric NUP98/HOXA9 transcript containing the amino terminal half of NUP98 fused in frame to HOXA9. These studies identify HOXA9 as an important human myeloid leukaemia gene and suggest an important role for nucleoporins in human myeloid leukaemia given that a second nucleoporin, NUP214, has also been implicated in human myeloid leukaemia.
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PMID:Fusion of the nucleoporin gene NUP98 to HOXA9 by the chromosome translocation t(7;11)(p15;p15) in human myeloid leukaemia. 856 53

The Rex protein of human T-cell leukemia virus type 1, like the functionally equivalent Rev protein of human immunodeficiency virus type 1, contains a leucine-rich activation domain that specifically interacts with the human nucleoporin-like Rab/hRIP cofactor. Here, this Rex sequence is shown to function also as a protein nuclear export signal (NES). Rex sequence libraries containing randomized forms of the activation domain/NES were screened for retention of the ability to bind Rab/hRIP by using the yeast two-hybrid assay. While the selected sequences differed widely in primary sequence, all were functional as Rex activation domains. In contrast, randomized sequences that failed to bind Rab/hRIP lacked Rex activity. The selected sequences included one with homology to the Rev activation domain/NES and a second that was similar to the NES found in the cellular protein kinase inhibitor alpha. A highly variant, yet fully active, activation domain sequence selected on the basis of Rab/hRIP binding retained full NES function even though this sequence preserved only a single leucine residue. In contrast, nonfunctional activation domain mutants that were unable to bind Rab/hRIP had also lost NES function. These data demonstrate that NES activity is a defining characteristic of the activation domains found in the Rev/Rex class of retroviral regulatory proteins and strongly support the hypothesis that the Rab/hRIP cofactor plays a critical role in mediating the biological activity of these NESs. In addition, these data suggest a consensus sequence for NESs of the Rev/Rex class.
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PMID:Protein sequence requirements for function of the human T-cell leukemia virus type 1 Rex nuclear export signal delineated by a novel in vivo randomization-selection assay. 875 20

The hypothesis that the cellular protein Crm1 mediates human immunodeficiency virus type 1 (HIV-1) Rev-dependent nuclear export posits that Crm1 can directly interact both with the Rev nuclear export signal (NES) and with cellular nucleoporins. Here, we demonstrate that Crm1 is indeed able to interact with active but not defective forms of the HIV-1 Rev NES and of NESs found in other retroviral nuclear export factors. In addition, we demonstrate that Crm1 can bind the Rev NES when Rev is assembled onto the Rev response element RNA target and that Crm1, like Rev, is a nucleocytoplasmic shuttle protein. Crm1 also specifically binds the Rev NES in vitro, although this latter interaction is detectable only in the presence of added Ran . GTP. Overexpression of a truncated, defective form of the nucleoporin Nup214/CAN, termed DeltaCAN, that retains Crm1 binding ability resulted in the effective inhibition of HIV-1 Rev or human T-cell leukemia virus Rex-dependent gene expression. In contrast, DeltaCAN had no significant affect on Mason-Pfizer monkey virus constitutive transport element (MPMV CTE)-dependent nuclear RNA export or on the expression of RNAs dependent on the cellular mRNA export pathway. As a result, DeltaCAN specifically blocked late, but not early, HIV-1 gene expression in HIV-1-infected cells. These data strongly validate Crm1 as a cellular cofactor for HIV-1 Rev and demonstrate that the MPMV CTE nuclear RNA export pathway uses a distinct, Crm1-independent mechanism. In addition, these data identify a novel and highly potent inhibitor of leucine-rich NES-dependent nuclear export.
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PMID:Inhibition of human immunodeficiency virus Rev and human T-cell leukemia virus Rex function, but not Mason-Pfizer monkey virus constitutive transport element activity, by a mutant human nucleoporin targeted to Crm1. 976 2

Chromosomal abnormalities involving the 11p15 or 11q22-23 bands have been reported in several types of human neoplasms including hematopoietic malignancies. The abnormalities are observed in therapy-related malignancies and less frequently in de novo myeloid malignancies. Abnormality of the MLL gene located on chromosome 11q23 has been well known in therapy-related myeloid malignancies, but it has been reported only recently that the inv(11)(p15q22) in de novo or therapy-related myeloid malignancies results in the fusion of NUP98 on chromosome 11p15 and DDX10 on chromosome 11q22. NUP98 is a nucleoporin that composes the nuclear pore complex and is the target gene in leukemia with the t(7;11)(p15;p15). The DDX10 gene encodes a putative adenosine triphosphate-dependent DEAD box RNA helicase. Here we present another patient with acute myelocytic leukemia (M4) transformed from chronic myelomonocytic leukemia with the inv(11) chromosome who had been treated with etoposide for a germ cell tumor. By reverse transcription polymerase chain reaction (RT-PCR) of the RNA from the leukemic cells of the patient, DDX10-NUP98 and NUP98-DDX10 fusion transcripts were detected. Our case confirms that the inv(11) is a rare chromosomal translocation that is associated with therapy-related or de novo myeloid malignancy and involves NUP98 and DDX10 but not MLL. RT-PCR of the fusion transcripts might be applied to the detection of a small number of leukemic cells in the bone marrow or blood of patients in remission or in the cells harvested for autologous transplantation.
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PMID:The inv(11)(p15q22) chromosome translocation of therapy-related myelodysplasia with NUP98-DDX10 and DDX10-NUP98 fusion transcripts. 1022 53

The reciprocal translocation t(7;11)(p15;p15) has been reported as occurring mainly in acute myelogenous leukaemia (AML) and the acute phase of chronic myelogenous leukaemia (CML). This translocation in AML involves both the nucleoporin gene NUP98 on 11p15 and the homeobox gene HOXA9 on 7p15. The invariant chimaeric NUP98/HOXA9 transcripts are a result of the fact that each breakpoint of the NUP98 and the corresponding breakpoint of the HOXA9 gene cluster occur within the same intron. Only one patient with myelodysplastic syndromes (MDS) carrying this chromosome aberration has been reported, but this study did not involve molecular analysis. We describe two patients with MDS associated with t(7;11): patient 1 was a Japanese man diagnosed with chronic myelomonocytic leukaemia; patient 2 was a Japanese woman with refractory anaemia with excess of blasts in transformation. Within a year both patients developed AML and showed multidrug resistance to chemotherapy. Southern blot analysis showed rearrangements of the NUP98 gene of the two patients and the HOXA9 gene of patient 2. Patient 1 had two types of the novel NUP98/HOXA9 fusion transcripts. Each of them lacked the common 141 bp NUP98 exon which was contained in the NUP98/HOXA9 fusion transcripts detected in patient 2 and the reported AML cases. These data indicated that t(7;11) could determine the development of various myeloid leukaemias and that the resultant chimaeric transcripts are heterogenous.
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PMID:Molecular heterogeneity of the NUP98/HOXA9 fusion transcript in myelodysplastic syndromes associated with t(7;11)(p15;p15). 1058 65

It has been demonstrated that the chromosomal translocation t(7;11)(p15;p15) in patients with human acute myelogenous leukemia (AML) and chronic myelogenous leukemia (CML) invariably involves fusion of the nucleoporin gene, NUP98, on chromosome 11 and the class 1 HOX gene, HOXA9, on chromosome 7, and that the fusion gene NUP98-HOXA9 is an important gene in myeloid leukemogenesis. Here are reported 2 novel chromosome 7p15 targets of the t(7;11)(p15;p15) chromosomal translocation in 2 patients with CML and myelodysplastic syndrome (MDS). Southern blot and polymerase chain reaction (PCR) analyses of leukemia cell DNA failed to show rearrangement of HOXA9, whereas NUP98 was found to be rearranged in both cases. Reverse transcription-PCR analysis using a NUP98 primer and a degenerate primer corresponding to the third helix of the homeodomain of HOXA demonstrated that NUP98 was fused in-frame to HOXA11 in the patient with CML and to HOXA13 in the patient with MDS. The chromosomal breakpoints on 7p15 were located within introns of HOXA11 or HOXA13 genes. In both patients chimeric NUP98-HOXA9 transcripts were also observed. These findings suggest that AbdB-type HOXA genes are common targets of t(7;11)(p15;p15) chromosomal translocations and that a single translocation can produce more than one NUP98-HOXA fusion gene, presumably because of altered splicing.
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PMID:Single-translocation and double-chimeric transcripts: detection of NUP98-HOXA9 in myeloid leukemias with HOXA11 or HOXA13 breaks of the chromosomal translocation t(7;11)(p15;p15). 1183 Apr 96

The Rev protein of human immunodeficiency virus type 1 (HIV-1) is essential for the nucleocytoplasmic transport of unspliced and partially spliced HIV mRNAs containing the Rev response element (RRE). In a yeast two-hybrid screen of a HeLa cell-derived cDNA expression library for human factors interacting with the Rev leucine-rich nuclear export sequence (NES), we identified a kinesin-like protein, REBP (Rev/Rex effector binding protein), highly homologous to Kid, the carboxy-terminal 75-residue region of which interacts specifically with the NESs of HIV-1 Rev, human T-cell leukemia virus type 1 Rex, and equine infectious anemia virus Rev but not with functionally inactive mutants thereof. REBP is a nuclear protein that colocalizes with Rev in the nucleoplasm and nuclear periphery of transfected cells. Specific, albeit weak, interaction between REBP and Rev could be demonstrated in coimmunoprecipitation assays in BSC-40 cells. REBP can modestly enhance Rev-dependent RRE-linked reporter gene expression both independently and in cooperation with the nucleoporin cofactor Rab/hRIP. Thus, REBP displays the characteristics expected of an authentic mediator of Rev NES function and may play a role in RRE RNA transport during HIV infection.
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PMID:A nuclear kinesin-like protein interacts with and stimulates the activity of the leucine-rich nuclear export signal of the human immunodeficiency virus type 1 rev protein. 1280 22

Chromosomal rearrangements of the 11p15 locus have been identified in hematopoietic malignancies, resulting in translocations involving the N-terminal portion of the nucleoporin gene NUP98. Fifteen different fusion partner genes have been identified for NUP98, and more than one half of these are homeobox transcription factors. By contrast, the NUP98 fusion partner in t(11;20) is Topoisomerase I (TOP1), a catalytic enzyme recognized for its key role in relaxing supercoiled DNA. We now show that retrovirally engineered expression of NUP98-TOP1 in murine bone marrow confers a potent in vitro growth advantage and a block in differentiation in hematopoietic precursors, evidenced by a competitive growth advantage in liquid culture, increased replating efficient of colony-forming cells (CFCs), and a marked increase in spleen colony-forming cell output. Moreover, in a murine bone marrow transplantation model, NUP98-TOP1 expression led to a lethal, transplantable leukemia characterized by extremely high white cell counts, splenomegaly, and mild anemia. Strikingly, a mutation to a TOP1 site to inactivate the isomerase activity essentially left unaltered the growth-promoting and leukemogenic effects of NUP98-TOP1. These findings, together with similar biologic effects reported for NUP98-HOX fusions, suggest unexpected, overlapping functions of NUP98 fusion genes, perhaps related to common DNA binding properties.
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PMID:NUP98-topoisomerase I acute myeloid leukemia-associated fusion gene has potent leukemogenic activities independent of an engineered catalytic site mutation. 1510 Jan 57

The HOM-C clustered prototype homeobox genes of Drosophila, and their counterparts, the HOX genes in humans, are highly conserved at the genomic level. These master regulators of development continue to be expressed throughout adulthood in various tissues and organs. The physiological and patho-physiological functions of this network of genes are being avidly pursued within the scientific community, but defined roles for them remain elusive. The order of expression of HOX genes within a cluster is co-ordinated during development, so that the 3' genes are expressed more anteriorly and earlier than the 5' genes. Mutations in HOXA13 and HOXD13 are associated with disorders of limb formation such as hand-foot-genital syndrome (HFGS), synpolydactyly (SPD), and brachydactyly. Haematopoietic progenitors express HOX genes in a pattern characteristic of the lineage and stage of differentiation of the cells. In leukaemia, dysregulated HOX gene expression can occur due to chromosomal translocations involving upstream regulators such as the MLL gene, or the fusion of a HOX gene to another gene such as the nucleoporin, NUP98. Recent investigations of HOX gene expression in leukaemia are providing important insights into disease classification and prediction of clinical outcome. Whereas the oncogenic potential of certain HOX genes in leukaemia has already been defined, their role in other neoplasms is currently being studied. Progress has been hampered by the experimental approach used in many studies in which the expression of small subsets of HOX genes was analysed, and complicated by the functional redundancy implicit in the HOX gene system. Attempts to elucidate the function of HOX genes in malignant transformation will be enhanced by a better understanding of their upstream regulators and downstream target genes.
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PMID:The pathophysiology of HOX genes and their role in cancer. 1564 70

Hox genes have been identified in chromosomal translocations involving the nucleoporin gene NUP98. Though the resulting chimeric proteins directly participate in the development of leukemia, the long latency and monoclonal nature of the disease support the requirement for secondary mutation(s), such as those leading to overexpression of Meis1. Models to identify such events and to study leukemic progression are rare and labor intensive. Herein, we took advantage of the strong transforming potential of NUP98-HOXD13 or NUP98-HOXA10 to establish preleukemic myeloid lines from bone marrow cells that faithfully replicate the first step of Hox-induced leukemogenesis. These lines contain early granulomonocytic progenitors with extensive in vitro self-renewal capacity, short-term myeloid repopulating activity and low propensity for spontaneous leukemic conversion. We exploit such lines to show that Meis1 efficiently induces their leukemic progression and demonstrate a high frequency of preleukemic cells in the cultures. Furthermore, we document that the leukemogenic potential of Meis1 is independent of its direct binding to DNA and likely reflects its ability to increase the repopulating capacity of the preleukemic cells by increasing their self-renewal/proliferative capacity. The availability of lines with repopulating potential and capacity for leukemic conversion should open new avenues for understanding progression of Hox-mediated acute myeloid leukemia.
Leukemia 2005 Apr
PMID:Transplantable cell lines generated with NUP98-Hox fusion genes undergo leukemic progression by Meis1 independent of its binding to DNA. 1574 44


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