Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.7.7.48 (transcriptase)
 9,479 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Mounting experimental evidence suggests that the TAT protein, released from human immunodeficiency virus-1 (HIV-1)-infected inflammatory cells, may genetically reprogram targeted cells within a localized environment to develop highly vascularized tumors of mesenchymal origin. The fibroblast growth factor (FGF) family of polypeptides has gained general acceptance as initiators of angiogenesis and functions as potent mitogens for mesoderm-derived cells. To evaluate a potential biological relationship between TAT and acidic FGF (FGF-1), primary murine embryonic fibroblasts either were transfected with the viral transactivator or were transduced (retrovirally mediated) with a secreted, chimeric form of the human polypeptide growth factor, human stomach tumor/Kaposi's sarcoma (hst/KS)FGF-1. Reverse transcriptase-polymerase chain reaction, Western blotting, in situ immunohistochemical, heparin affinity, DNA synthesis, and transient transfection techniques were used to confirm expression, localization, and functionality of the transgenes. Both transfected and transduced cells constitutively expressing either TAT or (hst/KS)FGF-1 adopted a transformed phenotype, maintained aggressive growth behavior, and demonstrated both induction of FGF-specific phosphotyrosyl proteins and nuclear association of FGF-1 and FGF-1 receptor. Increased levels of endogenous, murine FGF-1 mRNA (reverse transcriptase-polymerase chain reaction) and protein (immunoblot analysis) were apparent in both (hst/KS)FGF-1- and TAT-transformed cells. Medium conditioned by (hst/KS)FGF-1-transduced cells contained steady-state levels of biologically active FGF-1 which exhibited a representative molecular weight. Limited sodium dodecyl sulfate-polyacrylamide gel electrophoretic analysis of the conditioned medium from TAT-transformed cells demonstrated the appearance of FGF-1 as latent, high molecular weight complexes requiring reducing agents to activate full biological activity. Collectively, these results suggest that TAT induces the expression and secretion of FGF-1, which may be potentially relevant to the pathophysiological development of AIDS-Kaposi's sarcoma.
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PMID:The HIV-1 TAT protein induces the expression and extracellular appearance of acidic fibroblast growth factor. 754 39

In order to clone candidate tumor suppressor genes whose loss contributes to the pathogenesis of neuroblastoma (NB), we performed polymerase chain reaction (PCR) screening using a high-density sequence tagged site-content map within a commonly deleted region (chromosome band 1p36) in 24 NB cell lines. We found a approximately 480 kb homozygously deleted region at chromosome band 1p36.2 in one of the 24 NB cell lines, NB-1, and cloned the human homologue (KIF1B-beta) of the mouseKif1B-beta gene in this region. The KIF1B-beta gene had at least 47 exons, all of which had a classic exon-intron boundary structure. Mouse Kif1B is a microtubule-based putative anterograde motor protein for the transport of mitochondria in neural cells. We performed mutational analysis of the KIF1B-beta gene in 23 cell lines using 46 sets of primers and also an allelic imbalance (AI) analysis of KIF1B-beta in 50 fresh NB samples. A missense mutation at codon 1554, GTG (Gly) to ATG (Met), silent mutations at codon 409 (ACG to ACA) and codon 1721 (ACC to ACT), and polymorphisms at codon 170, GAT (Asp) to GAA (Glu), and at codon 1087, TAT (Tyr), to TGT (Cys), were all identified, although their functional significances remain to be determined. The AI for KIF1B-beta was slightly higher (38%) than those for the other two markers (D1S244, D1S1350) (35 and 32%) within the commonly deleted region (1p36). Reverse transcriptase-PCR analysis of the KIF1B-beta gene revealed obvious expression in all NB cell lines except NB-1, although decreased expression of the KIF1B-beta gene was found in a subset of early- and advanced-stage NBs. These results suggest that the KIF1B-beta gene may not be a candidate for tumor suppressor gene of NB.
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PMID:Genomic structure and mutational analysis of the human KIF1B gene which is homozygously deleted in neuroblastoma at chromosome 1p36.2. 1152 94

A reverse-transcriptase-subunit of telomerase (hTERT) derived peptide, GV1001, has been developed as a vaccine against various cancers. Here, we report an unexpected function of GV1001 as a cell-penetrating peptide (CPP). GV1001 was delivered into a variety of cells including various cancer cell lines and primary blood cells. Moreover, the delivered GV1001 was predominantly located in the cytoplasm of the cells, while a significantly higher proportion of TAT peptide was localized in the nucleus. Macromolecules such as proteins, DNA and siRNA, which were linked to GV1001 by direct covalent conjugation or non-covalent complexation through poly-lysine, were successfully delivered into cells, indicating that GV1001 can be used as a carrier for macromolecules. Expression of the delivered DNA, and lowered expression of the target gene by the delivered siRNA, suggest the potential therapeutic use of GV1001. Pull-down analysis identified Heat Shock Protein 90 (HSP90) and 70 (HSP70) as GV1001 interacting proteins. Treatment of Anti-HSP90 and HSP70 antibodies lowered the internalization of GV1001, indicating that the interaction is critical for the efficient internalization of GV1001. Collectively, the results of this study suggest the pharmaceutical potential of GV1001, already proven safe in clinical trials, as a carrier for the delivery of macromolecular therapeutics into cells, in addition to its own anti-cancer activity.
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PMID:Heat shock protein-mediated cell penetration and cytosolic delivery of macromolecules by a telomerase-derived peptide vaccine. 2382 87

Cell-penetrating peptides (CPPs), which can facilitate the transport of molecular cargo across the plasma membrane, have become important tools in promoting the cellular delivery of macromolecules. GV1001, a peptide derived from a reverse-transcriptase subunit of telomerase (hTERT) and developed as a vaccine against various cancers, reportedly has unexpected CPP properties. Unlike typical CPPs, such as the HIV-1 TAT peptide, GV1001 enabled the cytosolic delivery of macromolecules such as proteins, DNA and siRNA via extracellular heat shock protein 90 (eHSP90) and 70 (eHSP70) complexes. The eHSP-GV1001 interaction may have biological effects in addition to its cytosolic delivery function. GV1001 was originally designed as a major histocompatibility complex (MHC) class II-binding cancer epitope, but its CPP properties may contribute to its strong anti-cancer immune response relative to other telomerase peptide-based vaccines. Cell signaling via eHSP-GV1001 binding may lead to unexpected biological effects, such as direct anticancer or antiviral effects. In this review, we focus on the CPP effects of GV1001 bound to eHSP90 and eHSP70.
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PMID:The Telomerase-Derived Anticancer Peptide Vaccine GV1001 as an Extracellular Heat Shock Protein-Mediated Cell-Penetrating Peptide. 2794 29