Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0021051 (immunodeficiency)
 71,517 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Bloom syndrome is an autosomal recessive disorder associated with mutations in BLM gene encoding protein that belongs to the family of DNA helicases. It is characterized by predisposition to cancer, immunodeficiency, high sensitivity to UV and genomic instability of somatic cells. Here we show physical and functional cooperation between BLM and p53 proteins. Ectopic expression of BLM causes anti-proliferative effect in p53 wild type, but not in p53-deficient cells; p53-mediated transactivation is attenuated in primary fibroblasts from Bloom syndrome patients. BLM and p53 proteins physically interact in the cells as demonstrated in yeast and mammalian two-hybrid systems; interaction sites are mapped to 237-272 aa residues of BML and 285-340 aa of p53. Ectopic expression of the fragment of wild type BML containing p53-interactive domain suppresses p53-mediated transcription and interferes with p53-mediated growth inhibition. These observations indicate that BLM might be an important component of p53 function and suggest that Bloom Syndrome phenotype may in part be the result of the deregulation of the p53 tumor suppressor pathway.
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PMID:The Bloom syndrome protein interacts and cooperates with p53 in regulation of transcription and cell growth control. 1178 42

Werner syndrome (WS) is a recessive disorder characterized by premature senescence. Bloom syndrome (BS) is a recessive disorder characterized by short stature and immunodeficiency. A common characteristic of both syndromes is genomic instability leading to tumorigenesis. WRN and BLM genes causing WS and BS, encode proteins that are closely related to the RecQ helicase. We produced WRN-/-, BLM-/- and WRN(-/-)/BLM(-/-) mutants in the chicken B-cell line DT40. WRN-/- cells showed hypersensitivities to genotoxic agents, such as 4-nitroquinoline 1-oxide, camptothecin and methyl methanesulfonate. They also showed a threefold increase in targeted integration rate of exogenous DNAs, but not in sister chromatid exchange (SCE) frequency. BLM-/- cells showed hypersensitivities to the genotoxic agents as well as ultraviolet (UV) light, in addition to a 10-fold increase in targeted integration rate and an 11-fold increase in SCE frequency. In WRN(-/-)/BLM(-/-) cells, synergistically increased hypersensitivities to the genotoxic agents were observed whereas both SCE frequencies and targeted integration rates were partially diminished compared to the single mutants. Chromosomal aberrations were also synergistically increased in WRN(-/-)/BLM(-/-) cells when irradiated with UV light in late S to G(2) phases. These results suggest that both WRN and BLM may be involved in DNA repair in a complementary fashion.
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PMID:Werner and Bloom helicases are involved in DNA repair in a complementary fashion. 1184 Mar 41

Bloom syndrome (BS) is a rare autosomal recessive genetic disorder characterized by growth deficiency, unusual facies, sun-sensitive telangiectatic erythema, immunodeficiency and predisposition to cancer. The causative gene for BS is the BLM gene which encodes the BLM RecQ helicase protein. The BLM gene has 4437 bp and encodes 1417 amino acids. The detection of BLM gene mutations for laboratory diagnosis of BS is laborious and impractical, unless there are common mutations in a population. Here we describe the immunoblot and immunohistochemical analyses for the detection of the BLM protein using a polyclonal BLM antibody. The BLM gene and protein were consistently and clearly detected in Epstein-Barr virus (EBV)-transformed or phytohemagglutinin (PHA)-stimulated lymphoblasts from control and various human hematopoietic cell lines. In a 7-week old human fetal brain, the BLM gene expression was strongly detected in contrast to an adult human brain. The BLM protein was not detected in EBV-transformed lymphoblasts from three BS patients. By immunohistochemistry, nuclear dots of the BLM protein were detected in both EBV-transformed lymphoblasts and PHA-stimulated lymphoblasts from the control. However, in lymphoblasts from BS patients no nuclear dots of the BLM protein were detected. These results indicate that the combinational analysis of immunoblotting and immunohistochemistry is a useful approach to screening of BS, although a mutation analysis is necessary for a definitive diagnosis of BS.
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PMID:Expression of BLM (the causative gene for Bloom syndrome) and screening of Bloom syndrome. 1206 Aug 58

Treatment of patients with primary mediastinal B-cell lymphoma (PMBCL) remains controversial. We started a controlled clinical trial to evaluate the efficacy and toxicity of a conventional versus more intensive regimen of combined chemotherapy followed by radiotherapy to the mediastinum with the mantle technique. From 1989 to 1997, 68 patients diagnosed with previously untreated PMBCL, aged 18-65 years and negative for immunodeficiency virus test, were considered candidates to receive either conventional chemotherapy with CEOP-Bleo (cyclophosphamide 750 mg/m(2), vincristine 1.4 mg/m(2), prednisone 40 mg/m(2), epirubicin 70 mg/m(2), and bleomycin 10 mg/m(2)) or mega CEOP-Bleo (cyclophosphamide 1000 mg/m(2), epirubicin 120 mg/m(2), vincristine, prednisone, and bleomycin at the same doses) every 21 days for six cycles, followed by radiotherapy to the mediastinum with the mantle technique (35-45 Gy, mean 38 Gy). Complete response (CR) rates were not statistically different: 64% [95 percent confidence interval (CI): 58 percent to 70 percent] for conventional arm vs 81 percent (95 CI: 77-86 percent) in the intensive group (p=0.2). However, failure-free survival (FFS) and overall survival (OS) had statistical differences. At 5 years, actuarial FFS for patients treated with conventional chemotherapy was 51 percent (95 percent CI: 44-59 percent) compared to 70 percent (95 percent CI: 65-76 percent) in the intensive arm (p>0.01). OS rates were also different: 54 percent (95 percent CI: 48-57 percent) vs 70 percent (95 percent CI: 65-76 percent), respectively (p<0.01). Toxicity was mild and no therapy-related deaths were observed. At a median follow-up of 7.3 years, no second neoplasia or acute leukemia has been observed. The international prognostic index was not useful to define clinical risk in this selected group of patients. Multivariate analysis identified pleural and pericardial effusion and chemotherapy regimen as prognostic factors influencing FFS and OS. We feel that patients with PMBCL should be treated with more intensive, but not myeloablative chemotherapy, followed by adjuvant radiotherapy to achieve an improvement in outcome in this setting of patients. Patients with pleural or pericardial effusion are considered at high risk for failure with the actual programs of treatment and probably will be considered for experimental therapeutic approaches.
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PMID:Combined therapy in the treatment of primary mediastinal B-cell lymphoma: conventional versus escalated chemotherapy. 1218 5

Bloom syndrome (BS) is a genetic disorder associated with dwarfism, immunodeficiency, reduced fertility, and an elevated risk of cancer. To investigate the mechanism of this disease, we isolated from human HeLa extracts three complexes containing the helicase defective in BS, BLM. Interestingly, one of the complexes, termed BRAFT, also contains five of the Fanconi anemia (FA) complementation group proteins (FA proteins). FA resembles BS in genomic instability and cancer predisposition, but most of its gene products have no known biochemical activity, and the molecular pathogenesis of the disease is poorly understood. BRAFT displays a DNA-unwinding activity, which requires the presence of BLM because complexes isolated from BLM-deficient cells lack such an activity. The complex also contains topoisomerase IIIalpha and replication protein A, proteins that are known to interact with BLM and could facilitate unwinding of DNA. We show that BLM complexes isolated from an FA cell line have a lower molecular mass. Our study provides the first biochemical characterization of a multiprotein FA complex and suggests a connection between the BLM and FA pathways of genomic maintenance. The findings that FA proteins are part of a DNA-unwinding complex imply that FA proteins may participate in DNA repair.
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PMID:A multiprotein nuclear complex connects Fanconi anemia and Bloom syndrome. 1272 1

Bloom syndrome and ataxia-telangiectasia are autosomal recessive human disorders characterized by immunodeficiency, genome instability and predisposition to develop cancer. Recent data reveal that the products of these two genes, BLM and ATM, interact and function together in recognizing abnormal DNA structures. To investigate the function of these two molecules in DNA damage recognition, we generated double knockouts of ATM(-/-) BLM(-/-) in the DT40 chicken B-lymphocyte cell line. The double mutant cells were viable and exhibited a variety of characteristics of both ATM(-/-) and BLM(-/-) cells. There was no evidence for exacerbation of either phenotype; however, the more extreme radiosensitivity seen in ATM(-/-) and the elevated sister chromatid exchange seen in BLM(-/-) cells were retained in the double mutants. These results suggest that ATM and BLM have largely distinct roles in recognizing different forms of damage in DNA, but are also compatible with partially overlapping functions in recognizing breaks in radiation-damaged DNA.
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PMID:Disruption of the BLM gene in ATM-null DT40 cells does not exacerbate either phenotype. 1498

Bloom syndrome is a rare autosomal recessive genetic disorder characterized by growth deficiency, unusual facies, sun-sensitive telangiectatic erythema, immunodeficiency and predisposition to cancer. The causative gene for Bloom syndrome is BLM, which encodes the BLM RecQ helicase homolog protein. The first part of this review describes a long-term follow-up study of two Bloom syndrome siblings. Subsequently, the focus is placed on the functional domains of BLM. Laboratory diagnosis of Bloom syndrome by detecting mutations in BLM is laborious and impractical, unless there are common mutations in a population. Immunoblot and immunohistochemical analyses for the detection of the BLM protein using a polyclonal BLM antibody, which are useful approaches for clinical diagnosis of Bloom syndrome, are also described. In addition, a useful adjunct for the diagnosis of Bloom syndrome in terms of the BLM function is investigated, since disease cells must have the defective BLM helicase function. This review also discusses the nuclear localization signal of BLM, the proteins that interact with BLM and tumors originating from Bloom syndrome.
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PMID:Clinical features of Bloom syndrome and function of the causative gene, BLM helicase. 1513 5

Alternative targets of attack of the human immunodeficiency virus (HIV) are necessary in light of infection persistence due to onset of resistance after conventional reverse transcriptase and protease inhibitor therapy. We have recently shown that the cancer chemotherapeutic agent bleomycin (BLM) dose-dependently inhibits HIV-1 replication. The mechanism of this viral inhibition in vitro was investigated. Cell-free wild-type virions were affected directly by BLM in the presence of H2O2, as shown by a 38% decrease of viral infectivity. Viral inhibition by BLM did not proceed via NF-kappaB inhibition. The viral R/U5 DNA product was reduced by 70% without any effect on reverse transcriptase activity. In both a cell-free system as well as two-cell systems the antiviral dependence of BLM on iron and oxidant species was demonstrated. Bleomycin seems to inhibit HIV-1 replication through the same properties that make it a suitable anti-cancer agent. The results presented in this study describe a novel mechanism of HIV-1 inhibition with potential application in viral infections. The anti-HIV effects of BLM in patients receiving this drug in combination with HAART should be carefully monitored in order to evaluate the clinical significance of the findings described in this study.
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PMID:Mechanism of inhibition of the human immunodeficiency virus type 1 by the oxygen radical generating agent bleomycin. 1530 38

Bloom syndrome is a rare autosomal recessive genetic disorder characterized by lupus-like erythematous telangiectasias of the face, sun sensitivity, stunted growth, and immunodeficiency. Chromosome instability syndromes have a common feature, being associated at high frequency with neoplasia. BS is considered as one of the chromosome instability syndromes since the fibroblasts or lymphocytes of BS patients show excessive spontaneous chromosome instability. The causative gene of BS (BLM) was identified as a RecQ helicase homologue. In this review, we showed the characteristic phenotypes of BS, especially two Japanese siblings. In the latter of the review, the functional domains of BLM, those are nuclear localization signal and the interacting proteins such as ATM, are shown. Several lines of reports indicates that BLM helicase is involved in the re-initiation of DNA replication at sites where replication forks have arrested or collapsed. To elucidate the precise function of RecQ helicase in DNA repair and replication aims not only to improve our understanding of the molecular basis for tumorigenesis, but also to extend the range of potential therapeutic targets.
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PMID:The function of RecQ helicase gene family (especially BLM) in DNA recombination and joining. 1547 92

Bloom syndrome is a rare autosomal recessive genetic disorder characterized by lupus-like erythematous telangiectasias of the face, sun sensitivity, stunted growth, and immunodeficiency. Chromosome instability syndromes have a common feature, being associated at high frequency with neoplasia. BS is considered as one of the chromosome instability syndromes since the fibroblasts or lymphocytes of BS patients show excessive spontaneous chromosome instability. The causative gene of BS (BLM) was identified as a RecQ helicase homologue. In this review, we showed the characteristic phenotypes of BS, especially two Japanese siblings. In the latter of the review, the functional domains of BLM, those are nuclear localization signal and the interacting proteins such as ATM, are shown. Several lines of reports indicates that BLM helicase is involved in the re-initiation of DNA replication at sites where replication forks have arrested or collapsed. To elucidate the precise function of RecQ helicase in DNA repair and replication aims not only to improve our understanding of the molecular basis for tumorigenesis, but also to extend the range of potential therapeutic targets.
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PMID:The function of RecQ helicase gene family (especially BLM) in DNA recombination and joining. 1549 27


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