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:2.7.7.49 (reverse transcriptase)
31,746 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Differentiation choices in the haemopoietic and nervous systems are controlled in part by instructive factors. The cholinergic differentiation factor (CDF, also known as leukaemia inhibitory factor, LIF) affects the development of cultured cells from both systems. To understand the role of CDF/LIF during normal development in vivo, we have begun to localize its mRNA in the late fetal and postnatal rat. Application of reverse transcriptase-polymerase chain reaction and RNase protection methods reveals that CDF/LIF mRNA levels are developmentally modulated in both haemopoietic and neural tissues. A target tissue of cholinergic sympathetic neurons, the footpads that contain the sweat glands, express high levels of this mRNA (relative to mRNA for actin and beta 2-microglobulin). Levels in targets of noradrenergic neurons are lower, but do undergo significant changes during development. Signals are also detected in selective regions of the adult brain, and in embryonic skeletal muscle. This finding in muscle may be significant for motor neurons, because CDF/LIF is a trophic factor for these neurons in culture. Embryonic liver, neonatal thymus and postnatal spleen express CDF/LIF mRNA, and expression in gut is the highest of all tissues examined. The selective tissue distribution and developmental modulation of CDF/LIF mRNA expression support a role for this factor in the normal development of several organ systems.
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PMID:Further studies of the distribution of CDF/LIF mRNA. 142 9

Dysregulation in cytokines has been associated with melanomas. For example, loss of growth inhibition in advanced melanomas has been associated with interleukin-6 (IL-6) expression. Because IL-6 belongs to the hematopoietic cytokine family, which includes leukemia inhibitory factor (LIF) and interleukin-11 (IL-11), we examined the possibility of coordinate expression of LIF, IL-6, and IL-11 in three human melanoma cell lines derived from primary lesions (early) and in four lines derived from metastatic tumors (advanced). All lines examined produced at least low levels of LIF and IL-11 mRNA as measured by semiquantitative reverse transcriptase-polymerase chain reaction (RT-PCR). By enzyme-linked immunosorbent assay (ELISA), two of three early and three of four advanced lines were found to secrete LIF protein. IL-11 was assayed using growth of the responsive B9/11 cell line, but only one of seven lines made a low but measurable amount of IL-11. Cytokine protein production was not strictly correlated with mRNA abundance, nor was it strongly correlated with tumor staging. Recombinant LIF and IL-11 protein had no effect on the proliferation of any of the seven lines, suggesting that they do not act as autocrine growth factors for these melanomas. Assay of IL-6, IL-11, and LIF protein in conditioned medium from early and advanced melanoma lines gave no evidence of coordinate expression of these cytokines. We conclude that LIF and IL-11 production by melanomas may have some paracrine or endocrine function in the course of melanoma progression.
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PMID:Expression of leukemia inhibitory factor and interleukin-11 by human melanoma cell lines: LIF, IL-6, and IL-11 are not coregulated. 764 48

Using a cell sorter, CD16-CD56bright natural killer (NK) cells were sorted from decidual mononuclear cells at an early stage of pregnancy. These cells were examined by the reverse transcriptase-polymerase chain reaction (RT-PCR) method for their expression of mRNA coding for the following 12 cytokines: IL-1 beta, IL-2, IL-3, IL-4, IL-5, IL-6, granulocyte colony-stimulating factor (G-CSF), granulocyte-macrophage colony-stimulating factor (GM-CSF), macrophage colony-stimulating factor (M-CSF), tumor necrosis factor-alpha (TNF-alpha), interferon-gamma (IFN-gamma), and leukemia inhibitory factor (LIF). Although mRNA coding for every cytokine was detected in decidual mononuclear cells, mRNAs coding for only G-CSF, GM-CSF, M-CSF, TNF-alpha, IFN-gamma, and LIF were detected in CD16-CD56bright NK cells. Also, the supernatant of CD16-CD56bright NK cell cultures was found to contain G-CSF, GM-CSF, M-CSF, TNF-alpha, IFN-gamma, and LIF. These findings indicate that CD16-CD56bright NK cells produce many different cytokines and that these cytokines may play an important role in a successful pregnancy.
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PMID:Cytokine production by CD16-CD56bright natural killer cells in the human early pregnancy decidua. 768 93

As an approach for characterizing the molecules involved in the proliferation and differentiation of hematopoietic stem cells we have compared the ability of four murine stromal cell lines, MS-5, MS-K, both derived from Dexter cultures, BMS1 and BMS2 both derived from Whitlock-Witte cultures, to sustain murine long term hematopoiesis and to express the major hematopoietic cytokine genes. As opposed to the three other cell lines, MS-5 supports the maintenance of stem cells for up to 4-5 weeks. However, reconstituting stem cell output was reduced while clonogenic cell (day 12 and day 8 spleen colony-forming units, granulo-macrophagic, and erythroid progenitor cells) output was markedly increased. This hematopoietic-promoting activity is at least in part mediated by soluble molecules since medium conditioned with MS-5 cells was able to partially complement the nonsupportive cell line BMS1. The comparative study of the cytokine gene expression in MS-5 and in the nonsupportive cell lines included Northern blot and reverse transcriptase-polymerase chain reaction analysis of messenger RNA for interleukin-1, -3, -6, granulo-macrophage-colony-stimulating factor (GM-CSF), granulocyte-CSF, macrophage-CSF, stem cell factor, transforming growth factor-beta, tumor necrosis factor-alpha, macrophage inflammatory protein-1 alpha, and leukemia inhibitory factor. None of these molecules or their association were found to clearly confer to the MS-5 cell line its hematopoietic-promoting activity raising the possibility that uncharacterized molecule(s) would be involved in the proliferation and differentiation of stem cells.
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PMID:Hematopoietic-promoting activity of the murine stromal cell line MS-5 is not related to the expression of the major hematopoietic cytokines. 770 74

When 15-deoxyspergualin (DSG) was administered into [BALB/c-->C3H/He] bone marrow (BM) chimeras from day 14 to day 25, increased platelet counts were observed from day 25 to day 33. Twofold increase of platelet counts was observed in DSG-treated BM chimeras compared with phosphate buffered saline (PBS)-treated BM chimeras. By using reverse transcriptase-polymerase chain reaction (RT-PCR), several cytokine mRNA expressions were analyzed in order to clarify which cytokines are involved in thrombopoiesis. So far, interleukin-6 (IL-6), leukemia inhibitory factor (LIF), stem cell factor (SCF), and IL-11 have been reported to have potent thrombopoietic activity in vivo. Although some other cytokines such as IL-3 and granulocyte-macrophage colony-stimulating factor (GM-CSF) possess the capacity of thrombopoiesis, megakaryocytopoiesis is more marked in these cytokines. IL-6 mRNA expression was increased in spleen cells from DSG-treated BM chimeras from day 25 to day 32 and in bone marrow cells from day 19 to day 28. LIF mRNA expression was not significantly increased compared with PBS control. Although SCF mRNA expression was increased, the kinetics of increased SCF mRNA expression did not fit the kinetics of increased platelet counts. Increased mRNA expression in other hematopoietic cytokines, such as IL-3, granulocyte-colony stimulating factor (G-CSF) and GM-CSF were also observed, thus suggesting that these cytokines may synergistically support thrombopoiesis in concert with IL-6. These results suggest that IL-6 and other hematopoietic cytokines might induce increased platelet counts, although the involvement of thrombopoietin (TPO) and IL-11 should be analyzed in the future.
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PMID:A novel immunosuppressant 15-deoxyspergualin and thrombopoiesis. 795 88

Sindbis virus (SV) causes an acute encephalomyelitis in mice. A T cell-dependent inflammatory response is first detected 3 days after infection and includes T cells, B cells, and macrophages. The cytokines produced locally by intrinsic cells of the brain in response to infection and by infiltrating mononuclear cells and their contributions to outcome of infection have not been identified. Semiquantitative reverse transcriptase-PCR was used to evaluate the expression of mRNAs for IL-1 beta, IL-2, IL-4, IL-6, IL-10, TNF-alpha, leukemia inhibitory factor (LIF), and TGF-beta in the brain during fatal and nonfatal SV encephalitis of immunocompetent BALB/cJ and immunodeficient scid/CB17 mice. IL-1 beta and IL-6 mRNAs were detected in uninfected mice before infection and were up-regulated within 24 h. TGF-beta mRNA was also constitutively expressed in uninfected mice. LIF mRNA was occasionally detected in uninfected mice but increased in amounts only in BALB/cJ not scid mice after infection. TNF-alpha, IL-4, and IL-10 mRNAs were not found in uninfected mice but were induced within 24 h and continued to rise through 7 days after infection with substantially higher levels in BALB/cJ than scid mice. These data suggest that intrinsic brain cells produce IL-1, IL-4, IL-6, IL-10, LIF, and TGF-beta mRNAs in response to viral infection. IFN-gamma and IL-2 mRNAs were detected only in BALB/cJ mice and not until 3 days after infection with the initiation of inflammation. IL-4 and IL-10 mRNAs were more persistent and more easily detectable than IL-2 and IFN-gamma mRNAs. These data suggest a predominant type 2 cytokine response in the brain during SV encephalitis. BALB/cJ mice infected with a neurovirulent strain of SV (NSV), had 100% mortality, whereas NSV-infected scid mice developed persistent nonfatal infection. Inflammation was more intense in NSV-infected mice, however, no substantial differences in cytokine mRNA levels were detected when compared with mice with nonfatal SV infection suggesting that the cytokines measured do not in and of themselves lead to fatal central nervous system disease.
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PMID:Intracerebral cytokine mRNA expression during fatal and nonfatal alphavirus encephalitis suggests a predominant type 2 T cell response. 830 Nov 32

Many reports document that bone marrow stromal cells or their cytokine products can influence the formation of B cells in vitro. Most of this data comes from studies using lines or clones of stromal cells after multiple passage in culture, which could alter gene expression. Our aim in the present study was to determine which cytokines are produced by normal stromal cells under conditions that promote B lymphopoiesis. Primary cultured stromal cells were isolated on FACS from active Whitlock cultures. These cells proved to be relatively homogeneous in expression of cell surface antigens (CD44, VCAM-1, MECA10, and a molecule marked by hamster anti-mouse 8.28 monoclonal antibody). RNA from unselected Whitlock cultured adherent cells and sorted stromal cells from the same cultures were subjected to reverse transcriptase polymerase chain reaction to assess constitutive expression of several cytokine genes. Transcripts for interleukin-1 beta (IL-1 beta), IL-7, macrophage (M)-colony-stimulating factor (CSF), stem cell growth factor (SCGF), insulin-like growth factor 1 (IGF-1) and occasionally leukemia inhibitory factor were detected in RNA from intact cultures. Messages for IL-7, M-CSF, and SCGF were selectively contained within the isolated stromal cell fraction; whereas, IL-1 beta was found solely within the non-stromal cell fraction. IGF-1 was transcribed by both stromal cells and macrophages in Whitlock cultures. No evidence was found for constitutive expression of IL-1 alpha, IL-4, IL-6, or granulocyte-macrophage-CSF. This is in contrast to some reported stromal cell lines and clones. To determine if all primary stromal cells from active lymphopoietic cultures produced IL-7, the isolated cells were stained to reveal cytoplasmic IL-7 protein. A majority of the cells produced IL-7, but about 20% had no detectable IL-7 protein. Taken together, our results suggest that the primary stromal cells are a distinguishable cell type but functional subsets may exist. In regard to the differences in IL-7 production, the primary cell phenotype appears to mirror at least one division noted among the stromal cell lines.
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PMID:Cytokine production and heterogeneity of primary stromal cells that support B lymphopoiesis. 834 42

The pathogenesis of the dementia associated with human immunodeficiency virus (HIV) infection is unclear, but has been postulated to be due to indirect effects of HIV infection including the local production of cytokines. To determine which cytokines are produced in the nervous system and to identify any correlations with dementia, cytokine and HIV messenger RNA expression was analyzed by reverse transcriptase-polymerase chain reaction in the brains from 24 HIV-infected patients with and without dementia and 9 HIV-uninfected control subjects. Levels of tumor necrosis factor-alpha messenger RNA were significantly higher and levels of interleukin (IL)-4 messenger RNA were significantly lower in demented compared to nondemented HIV-infected patients. Demented patients also had lower IL-1 beta levels than did nondemented patients. No significant differences were detected in the amounts of leukemia inhibitory factor, IL-6, transforming growth factor-beta 1 and -beta 2, monokine induced by gamma interferon-2 (MIG-2), or interferon-gamma messenger RNAs. IL-10 and IL-2 messenger RNAs were undetectable in all brains examined. Cytokine messenger RNA levels in nondemented HIV-positive patients were similar to those in HIV-negative control subjects. HIV transcripts were more abundant in subcortical white matter than in the basal ganglia, cortex, or deep white matter. Our findings suggest a possible role for tumor necrosis factor-alpha in the development of neurological dysfunction. Increased levels of tumor necrosis factor-alpha messenger RNA were not associated with increased levels of IL-1 beta messenger RNA, suggesting differential regulation of these monokines in acquired immunodeficiency syndrome dementia.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Intracerebral cytokine messenger RNA expression in acquired immunodeficiency syndrome dementia. 849 37

There is considerable evidence to suggest that polypeptide growth factors from either the oviduct or the endometrium can control preimplantation development of the mammalian embryo. These act directly through receptors expressed on the embryo. In addition, embryos also produce growth factors. The reverse transcriptase-polymerase chain reaction (RT-PCR) was used to determine the pattern of expression of mRNAs encoding several growth factor ligand and receptor genes throughout preimplantation development of cryopreserved human embryos. Transcripts encoding the receptor for c-fms, the receptor for colony-stimulating factor-1 (CSF-1), and c-kit (the receptor for stem cell factor [SCF]) were expressed throughout preimplantation development. Other growth factor ligand and receptor transcripts were expressed in a stage-specific manner: these included receptors for interleukin (IL)-6 (IL-6R), leukemia inhibitory factor (LIFR), tumor necrosis factor alpha (TNF alpha) (TNFRp80 and TNFRp60), and gp130. The transcripts for gp130 and the ligand SCF showed stage-specific splice variants. Blastocysts expressed a novel cDNA encoding gp130, which predicts a truncated form lacking the intracellular signaling domain. No expression of mRNAs encoding LIF, CSF-1, or the cloned receptor for platelet-activating factor was seen in any embryonic stage studied. We have shown that RT-PCR provides a sensitive and powerful method for identifying transcripts encoding growth factors and their receptors in single human embryos. The method is economical, allowing the expression pattern of many genes to be determined from a single embryo. These data are important in defining which cytokines may be involved in regulating human preimplantation development and when they may act.
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PMID:Stage-specific expression of cytokine and receptor messenger ribonucleic acids in human preimplantation embryos. 854 94

Stromal cell lines were established by irradiating adherent layers of bone marrow and spleen cells in Dexter-type long-term culture with X-rays. Some of these cell lines support myelopoiesis and/or B lymphopoiesis in vitro. Furthermore, the characteristics of these stromal cell lines were studied. Cytokine activity was detected in the conditioned media from all hematopoietic-supportive and non-supportive stromal cells. Quantitative reverse transcriptase-polymerase chain reaction analysis revealed that the mRNAs of macrophage colony-stimulating factor and stem cell factor, but not that of Interleukin-3, were detectable in all the hematopoietic-supportive and non-supportive stromal cell lines. The transcripts of granulocyte colony-stimulating factor, interleukin-6, interleukin-7, and leukemia inhibitory factor were expressed in a wide variety of cell lines. Most stromal cell lines synthesized mRNA of c-mpl, the ligand of which stimulates megakaryopoiesis and thrombopoiesis. These observations indicate that the pattern of mRNA expression of cytokines is not correlated with the hematopoietic-supportive ability of stromal cell lines. There was a significant difference in the efficiency of adhesion of lineage marker-negative bone marrow cells to fibroblasts and stromal cell lines. This appears to be correlated with the hematopoietic-supportive ability of the stromal cell lines.
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PMID:Characterization of murine stromal cell clones established from bone marrow and spleen. 865 75


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