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:2.7.10.1 (ERK)
95,504 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The ability to evaluate the patterns and levels of human immunodeficiency virus type I (HIV-1)-specific RNA in latently and productively-infected cell lines, and primary human cells, is critical to the understanding of HIV-1 expression in cell cultures and possibly in vivo. We have developed a quantitative reverse transcriptase-polymerase chain reaction (RT-PCR), utilizing in vitro transcribed RNA standards, to evaluate the copy number per cell and per microgram of total cellular RNA of multiply-spliced, unspliced and total HIV-1-specific RNA species. The latently-infected monocytic and T-lymphocyte cell lines, U1 and ACH-2 respectively, are shown to express between 10(4) to 10(6) copies of total HIV-1-specific RNA per cell, based on the state of cellular stimulation. A dramatic increase of unspliced HIV-1-specific RNA in both the U1 cell line and the ACH-2 cell line is demonstrated by this quantitative RT-PCR, 24 h after stimulation with phorbol esters. These data suggest that a single integrated HIV-1 provirus can rapidly express large quantities of HIV-1-specific RNA. Quantitative RT-PCR, for HIV-1-specific transcripts, should prove extremely useful in evaluating retroviral load and pathogenesis in cell cultures and in vivo.
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PMID:A quantitative reverse transcriptase-polymerase chain reaction for HIV-1-specific RNA species. 128 31

The majority of infants born to HIV-positive mothers are not infected in utero, suggesting that the pregnancy factors produced by fetal trophoblasts may provide protection against HIV-1 infection. Except for steroid female hormones, little is known of other pregnancy factors that may regulate either resistance or susceptibility to HIV-1. Human chorionic gonadotropin (hCG)--the major glycoprotein produced by the placental trophoblast throughout the pregnancy--was tested on reverse transcriptase activity in HIV-infected ACH-2 lymphocytes and U1 monocytes. The results suggest that low non-cytotoxic doses of hCG (0.01-1.0 IU range) may inhibit viral replication in maternal blood cells.
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PMID:Effect of human chorionic gonadotropin (hCG) on reverse transcriptase activity in HIV-1 infected lymphocytes and monocytes. 138 34

The pleiotropic immunoregulatory cytokine transforming growth factor beta (TGF-beta) potently suppresses production of the human immunodeficiency virus (HIV), the causative agent of the acquired immunodeficiency syndrome, in the chronically infected promonocytic cell line U1. TGF-beta significantly (50-90%) inhibited HIV reverse transcriptase production and synthesis of viral proteins in U1 cells stimulated with phorbol myristate acetate (PMA) or interleukin 6 (IL-6). Furthermore, TGF-beta suppressed PMA induction of HIV transcription in U1 cells. In contrast, TGF-beta did not significantly affect the expression of HIV induced by tumor necrosis factor alpha (TNF-alpha). These suppressive effects were not mediated via the induction of interferon alpha (IFN-alpha). TGF-beta also suppressed HIV replication in primary monocyte-derived macrophages infected in vitro, both in the absence of exogenous cytokines and in IL-6-stimulated cultures. In contrast, no significant effects of TGF-beta were observed in either a chronically infected T cell line (ACH-2) or in primary T cell blasts infected in vitro. Therefore, TGF-beta may play a potentially important role as a negative regulator of HIV expression in infected monocytes or tissue macrophages in infected individuals.
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PMID:Transforming growth factor beta suppresses human immunodeficiency virus expression and replication in infected cells of the monocyte/macrophage lineage. 170 78

A T cell clone (ACH-2) derived from T cells infected with HIV-1 was found to produce HIV-1 in response to stimulation with a monokine-enriched supernatant prepared by culturing human monocyte/macrophages with bacterial LPS (LPS-MO SN). Monokine induction of ACH-2 cells resulted in augmented virus production reflected by an increase in reverse transcriptase activity and in the synthesis of all major viral proteins. Examination of the cells by indirect immunofluorescence revealed that 10 to 15% of uninduced cells constitutively expressed HIV proteins, whereas 100% showed positive immunofluorescence in response to LPS-MO SN. This induction of virus by LPS-MO SN resulted in approximately a 100-fold increase of infectious virus production over uninduced ACH-2 cells. LPS alone could not induce HIV-1 expression, whereas LPS-MO SN resulted in the greatest virus expression. Cell separation studies confirmed the source of the inducing factor(s) to be cells bearing the mature monocyte/macrophage marker, Leu M3. Biochemical fractionation of the LPS-MO SN suggested that one or more factors, having apparent Mr of approximately 45 kDa, were involved in this induction. Absorption of the LPS-MO SN with immunoaffinity gels specific for human TNF-alpha was shown to completely remove the HIV inducing activity for the ACH-2 cell line.
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PMID:Monokine regulation of human immunodeficiency virus-1 expression in a chronically infected human T cell clone. 246 7

Promonocytic (U1) and T lymphocytic (ACH-2) cell lines chronically infected with human immunodeficiency virus type 1 (HIV-1) constitutively express low levels of virus, but expression can be induced by phorbol esters and cytokines. Whereas ACH-2 cells produce infectious virions, U1 cells produce defective, noninfectious particles. Although 3'-azido-3'-deoxythimidine (AZT) prevented acute HIV infection of susceptible cells, it did not prevent the induction of HIV expression in the infected cell lines. In contrast, interferon alpha (IFN-alpha) inhibited the release of reverse transcriptase and viral antigens into the culture supernatant after phorbol ester stimulation of both cell lines. Further, IFN-alpha suppressed the production or release (or both) of whole HIV virions, but had no effect on the amount of cell-associated viral proteins. Also, after phorbol ester stimulation of ACH-2 cells, IFN-alpha reduced the number of infectious viral particles secreted into the culture supernatant, but had no effect on the infectivity of cell-associated virus. These findings lend support to the combined use of antiviral agents that have action at both the early (AZT) and the late (IFN-alpha) stages of HIV replication.
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PMID:Interferon-alpha but not AZT suppresses HIV expression in chronically infected cell lines. 247 Jan 48

Tumor necrosis factor alpha (TNF-alpha), also known as cachectin, was demonstrated to induce the expression of human immunodeficiency virus (HIV) in a chronically infected T-cell clone (ACH-2). Concentrations of recombinant TNF-alpha as low as 50 pg/ml induced a significant increase over background of HIV expression in the ACH-2 cells as determined by supernatant reverse transcriptase activity. The HIV-inducing effects of TNF-alpha could not be explained by toxic effects on the cells. In addition, both the uninfected parental cell line (A3.01) and the infected ACH-2 cells were shown to have high-affinity receptors for TNF-alpha. Transient-transfection experiments demonstrated that the inductive effects of TNF-alpha were due to specific activation of the HIV long terminal repeat. These studies provide evidence that TNF-alpha may play a role in the mechanisms of pathogenesis of HIV infection.
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PMID:Tumor necrosis factor alpha induces expression of human immunodeficiency virus in a chronically infected T-cell clone. 278 70

C-type particles produced by a tissue culture-adapted BALB/c myeloma were characterized. It was determined that although the particles were morphologically and antigenically similar to murine leukemia and sarcoma virus, the size of their RNA was different, they lacked RNA-dependent DNA polymerase, they were unstable in NET buffer, sucrose and citrate but were stable in glycerol and Earle balanced salt solution, and they behaved differently from oncornaviruses when treated with ether and detergent.
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PMID:Characterization of C-type particles produced by a tissue culture-adapted murine myeloma. 412 86

The RET proto-oncogene, which encodes a receptor tyrosine kinase, displays multiple alternative splicing variants. Splicing of sequences 3' of exon 19 to generate several coding and untranslated region (UTR) sequences has been previously reported. We have sequenced the full length RET coding region and characterized the transcripts and 3' UTRs generated by alternative splicing of the RET 3' terminus. These analyses were performed using both RET cDNA cloned from a pheochromocytoma library and reverse transcriptase PCR products generated using RNA from a neuroblastoma cell line (LA-N-2). Three different carboxyl termini were identified. In addition to the nine and 51 terminal amino acid forms already known, we identified a third with 43 terminal amino acids predicted to encode a novel RET protein isoform. A total of 3621 base pairs of DNA 3' of exon 19, which spans the alternatively spliced exons and RET UTRs, was sequenced. Four polyadenylation sites were identified. The observed combinations of polyadenylation sites and 3' coding sequence suggest that RET transcripts with up to 10 different 3' sequences and up to 40 different full length RET transcripts may exist.
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PMID:Characterization of RET proto-oncogene 3' splicing variants and polyadenylation sites: a novel C-terminus for RET. 747 23

Inappropriate expression of Her-2/neu (ERBB2) gene has been associated with impaired breast cancer prognosis, suggesting a functional role in tumor progression. Herein we describe a quantitative method for analysis of Her-2/neu gene messenger RNA (mRNA), which employs reverse transcriptase polymerase chain reaction (RT-PCR) on a 10-microns cryostat section. The technique combines modified RNA extraction with complementary DNA (cDNA) synthesis to achieve a high level of sensitivity. Utilizing this PCR-based gene expression assay, we were able to quantitate variable amounts of Her-2/neu mRNA in cell lines with established levels of gene expression and in clinical human breast cancer specimens. In clinical samples, mRNA levels correlated with intensity of immunoperoxidase staining for corresponding oncoprotein. We conclude that PCR-based mRNA quantitation can be applied to quantitative analysis of Her-2/neu gene expression, and potentially many other genes, in samples of limited size.
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PMID:Quantitative analysis of Her-2/neu (ERBB2) gene expression using reverse transcriptase polymerase chain reaction. 750 83

Human tumors can constitutively express cytokines and growth factors, but the extent of this expression has not been investigated. Using 44 different probes to cytokines, growth factors, and their receptors, we tested 21 melanoma and 5 melanocyte cultures for RNA transcript expression by reverse transcriptase-polymerase chain reaction. With 30 amplification cycles, expression of the cytokines interleukin (IL)-1 beta, IL-6, leukemia inhibitory factor (LIF), IL-7, gro alpha, IL-8 and the p35 chain of IL-12 was detected in more than 60% of melanomas. Concomitant receptors for IL-6 and IL-7 were also detected. IL-1 alpha, IL-5, Rantes, IL-10, interferon (IFN)-beta, tumor-necrosis factor (TNF)-alpha, G-colony-stimulating factor (CSF) and GM-CSF were expressed at lower levels. Melanocytes showed greatly reduced cytokine RNA transcripts, and only gro alpha was consistently detected. No expression of IL-2, IL-3, IL-4, IL-9, the p40 chain of IL-12, IFN-alpha or IFN-gamma RNA transcripts was detected in melanomas or melanocytes. The growth factors expressed by melanomas and, after further signal amplification, by melanocytes were transforming growth factor (TGF)-alpha, epidermal growth factor (EGF), TGF-beta, endothelial-cell growth factor (ECGF), basic-fibroblast growth factor (bFGF), nerve growth factor (NGF) and steel. The receptors EGFR, FGFR, NGFRp70 and c-kit were also expressed by melanomas and melanocytes. These results point to new possible autocrine and paracrine pathways in melanoma biology.
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PMID:Expression of cytokine/growth factors and their receptors in human melanoma and melanocytes. 750 78


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