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:2.7.7.48 (transcriptase)
9,479 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We have established a dermal fibroblast-like stromal cell line, DFB-1, and a clone, 12E2, from epidermal sheets prepared from the skin of BALB/c mouse ears by trypsin digestion. They were suggested to be fibroblasts or myofibroblasts, as 1) they were polygonal or spindle-shaped under the phase-contrast microscope, 2) they did not possess any tonofilaments or desmosomes, and 3) they did not express any marker for bone marrow-derived cells or macrophages. Interestingly, these cells showed a unique phenomenon of "pseudo-emperiporesis," which was first recognized in the interaction between thymic nurse cells and thymocytes. Namely, two T-cell clones and one T-cell hybridoma migrated beneath the cytoplasmic projections of the fibroblast-like cutaneous stromal cells in culture. Furthermore, secretion of interleukin 7 by these cells was confirmed by bioassay using an IL-7-dependent cell line and by inhibition with anti-interleukin 7 antibody, and the expression of interleukin 7 mRNA was also demonstrated in these cells by a combination of reverse-transcriptase polymerase chain reaction and Southern blot analysis. These data strongly suggest the presence of unique stromal cells even in the skin, probably at the upper dermis, which can function like the nurse cells in the thymus. These stromal cells may play a crucial role in cutaneous immunophysiology.
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PMID:Cultured murine dermal cells can function like thymic nurse cells. 751 55

Cytokines, in particular IFN-gamma and IL-12, are important in host protection against infection with Toxoplasma gondii. This parasite is a major cause of congenital infection and morbidity in immunosuppressed persons, especially those with AIDS. IL-7, a monomeric protein produced by bone marrow stromal cells and fetal thymus, is able to induce the proliferation of pro-B cells and CD4+ and CD8+ T cells, and to enhance cytotoxicity of CTL and NK cells. Inbred mice were infected with a lethal dose of T. gondii and given IL-7 twice daily. Mice treated with IL-7 beginning at the time of infection survived, whereas mice either treated after infection or not treated died. Phenotypic analysis of splenocytes identified an expansion of NK (asialo GM1+) cells and CD8+ T cell populations. In vivo depletion of NK (asialo GM1+) and CD8+ T cells showed that cells expressing these phenotypes were important for maintaining protection against the parasite. IFN-gamma depletion resulted in complete reversal of the protective effect of IL-7 administration. In vivo depletion of endogenous IL-7 enhanced susceptibility to infection. Cytokine analysis by semiquantitative reverse-transcriptase PCR showed that IL-7 enhances the IFN-gamma response and furthermore reverses the parasite-mediated down-regulatory response on IL-2. These observations indicate that exogenous administration of human rIL-7 is able to protect mice against acute parasite challenge by stimulating IFN-gamma production and augmenting the CD8+ T cell-mediated CTL response.
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PMID:IL-7 stimulates protective immunity in mice against the intracellular pathogen, Toxoplasma gondii. 759 82

Microvascular murine endothelial cells lines transformed by middle T oncogene of polyoma virus maintain the biological characteristics of nontransformed microvascular endothelial cells (EC). By using cell lines originated from different anatomical districts (thymus, brain, heart, and skin), we demonstrated that murine granulocyte-colony-stimulating factor (G-CSF) induces proliferation of murine microvascular endothelial cells at nanomolar concentrations without any cooperation with fetal calf serum. The proliferative effect on murine cells is less than that elicited by epidermal growth factor (EGF), used as standard for this function. G-CSF also promotes the migration of tEnd.1 endothelial cell line assayed by Boyden chamber technique. The analysis of transcript for G-CSF receptor (G-CSFR) by Northern blot hybridization and by reverse-transcriptase polymerase chain reaction (RT-PCR) shows that these cell lines have specific mRNA, with the size of that present in myeloid cells. These results indicate that G-CSF operates in the microvascular endothelial cells by a mechanism related to the presence of a specific receptor.
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PMID:Proliferative and migratory responses of murine microvascular endothelial cells to granulocyte-colony-stimulating factor. 768 23

A cDNA coding for the beta 4 subunit of murine integrin (m beta 4) has been cloned and sequenced using mRNA from a murine lung carcinoma as the template. The 5' sequence contains two AUG codons, the second of which initiates synthesis of the mature protein. The cDNA sequence has an open reading frame coding for 1748 amino acids (aa), including a signal peptide, cysteine-rich region, serine- and threonine-rich region, transmembrane domain, and a cytoplasmic domain of over 1000 aa. Overall, the deduced m beta 4 aa sequence has 88% identity with the human beta 4 subunit (h beta 4) sequence deduced from the sequence of placental mRNA. Reverse transcriptase-polymerase chain reaction using primers flanking splice sites for two variant forms of h beta 4 transcripts provided evidence for alternate splicing of RNA in the murine spleen and to a lesser extent in the skin, uterus, and thymus but was found at only one of the two alternative sites. Five potential glycosylation sites present in the extracellular domain of h beta 4 are conserved in m beta 4. One tyrosine in the terminal region of the cytoplasmic domain (position 1600) is conserved between m beta 4 and h beta 4 and has the consensus sequence for tyrosine phosphorylation. Finally, a genomic restriction map of m beta 4 shows that the gene is about 40 kb in length. No restriction-fragment length polymorphisms were detected between BALB/c liver and BALB/c lung carcinoma DNA.
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PMID:Sequence of a cDNA encoding the beta 4 subunit of murine integrin. 835 87

Differentiation of hematopoietic progenitor cells into T lymphocytes generally occurs in the unique environment of the thymus, a feature that has hindered efforts to model this process in the laboratory. We now report that thymic stromal cultures from rhesus macaques can support T-cell differentiation of human or rhesus CD34+ progenitor cells. Culture of rhesus or human CD34+ bone marrow-derived cells depleted of CD34+ lymphocytes on rhesus thymic stromal monolayers yielded CD3+CD4+CD8+, CD3+CD4+CD8-, and CD3+CD4-CD8+ cells after 10 to 14 days. In addition to classical T lymphocytes, a discrete population of CD3+CD8loCD16+CD56+ cells was detected after 14 days in cultures inoculated with rhesus CD34+ cells. CD3+ T cells arising from these cultures were not derived from contaminating T cells present in the CD34+ cells used to inoculate thymic stromal monolayers or from the thymic monolayers, as shown by labeling of cells with the lipophilic membrane dye PKH26. Expression of the recombinase activation gene RAG-2, which is selectively expressed in developing lymphocytes, was detectable in thymic cultures inoculated with CD34+ cells but not in CD34+ cells before thymic culture or in thymic stromal monolayers alone. Reverse transcriptase-polymerase chain reaction analysis of T cells derived from thymic stromal cultures of rhesus and human CD34+ cells showed a polyclonal T-cell receptor repertoire. T-cell progeny derived from rhesus CD34+ cells cultured on thymic stroma supported vigorous simian immunodeficiency virus replication in the absence of exogenous mitogenic stimuli. Rhesus thymic stromal cultures provide a convenient means to analyze T-cell differentiation in vitro and may be useful as a model of hematopoietic stem cell therapy for diseases of T cells, including acquired immunodeficiency syndrome.
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PMID:In vitro T lymphopoiesis of human and rhesus CD34+ progenitor cells. 863 59

There are two distinct lineages of T cells: T-cell receptor (TCR) alphabeta-bearing cells (alphabeta T cells) and TCR gammadelta-bearing cells (gammadelta T cells). All of the alphabeta T cells and most subsets of gammadelta T cells develop in the thymus. It has been demonstrated that the protein tyrosine phosphatase CD45 plays a pivotal role in the intrathymic development of alphabeta T cells. Thymocyte maturation is arrested at the transitional stage from immature CD4+ CD8+ double-positive to mature CD4+ or CD8+ single-positive cells after CD45 exon 6 gene disruption. In this study, we examined whether Vgamma3 dendritic epidermal T cells (DETC), a subset of thymus-dependent gammadelta T cells uniquely residing in the murine epidermis, are altered in the CD45 exon 6-deficient mice. In situ immunolabeling on epidermal sheets demonstrated that the CD45-deficient mice had a normal density and immunophenotype of Vgamma3 DETC compared with the wild-type control mice. Reverse transcriptase polymerase chain reaction revealed that similar levels of Vgamma3 TCR mRNA were present in the epidermis of CD45-deficient mice and wild-type controls. Flow cytometry demonstrated no significant difference in the proportion of Vgamma3 T cells in the epidermis between the genotypes. In addition, Vgamma2 T cells, another subset of gammadelta T cells, were also examined by flow cytometry. The frequency of Vgamma2 T cells in lymph nodes was normal in the CD45-deficient mice. Our results indicate that although CD45 is crucial for the development of alphabeta T cells, this molecule is not necessary for the thymic maturation of gammadelta T cells, including Vgamma3 DETC and Vgamma2 T cells.
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PMID:CD45 molecule in gammadelta T-cell generation: disruption of CD45 exon 6 does not affect Vgamma3 dendritic epidermal T-cell development. 924 17

Some natural and glycon-modified dNTPs with beta,gamma-pyrophosphate substitution at the triphosphate residue were synthesized and studied to evaluate the effect of these modifications on substrate properties of dNTPs in DNA synthesis catalyzed by human placental DNA polymerases alpha and beta, avian myeloblastosis virus reverse transcriptase, and calf thymus terminal deoxynucleotidyl transferase. Reverse transcriptase proved to be the enzyme least specific to such modifications; the substrate activity of beta,gamma-methylenediphosphonate substituted dTTP and 3'-azido-3'-deoxy-dTTP decreased in the following order: CF2 = CHF > CBr2 > CFMe >> CH2. This order is individual for each DNA polymerase. It is interesting to mention that beta,gamma-CBr2 substituted dTTP is neither a substrate nor an inhibitor of DNA polymerase beta. This specificity distinguishes DNA polymerase beta from other DNA polymerases studied.
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PMID:Effect of triphosphate modifications in 2'-deoxynucleoside 5'-triphosphates on their specificity towards various DNA polymerases. 923 75

Interleukin (IL)-12 is a heterodimeric cytokine consisting of 35 and 40 kDa subunits, produced primarily by phagocytic cells in response to bacteria or bacterial products. IL-12 is important in the regulation of both innate and antigen-specific immunity through its stimulatory effects on NK cells and cytotoxic lymphocytes. Reverse transcriptase-polymerase chain reaction with primers derived from human sequence was used to clone the p35 and p40 subunits of porcine IL-12. Predicted amino acid sequences for both subunits are approximately 85% homologous to their human cognates but contain a 3aa addition and a 4aa deletion in p35 and p40 subunits, respectively. The high degree of similarity indicates the proteins may be cross reactive, an important consideration in pig-human xenotransplantation. Both subunits of pIL-12 are constitutively expressed in a variety of porcine tissues. Highest levels of the p40 subunit were found in lymphoid tissues including inguinal and mesenteric lymph nodes, Peyer's patches, spleen and thymus. The p35 subunit was also detected in these tissues. Levels of mRNA encoding the p40 subunit, but not the p35 subunit, were rapidly increased in alveolar macrophages stimulated with lipopolysaccharide or killed Staphylococcus aureus. Thus, the heterodimeric subunits appear to be differentially regulated at the transcriptional level. Since p40 also self-associates to form inactive homodimers, differential expression may be a mechanism for regulating IL-12 activity.
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PMID:Molecular cloning and mRNA expression of porcine interleukin-12. 923 44

The gene for the murine interleukin-11 receptor alpha chain (mIL-11R alpha) contains two loci (1 and 2), of which locus 2 is restricted to only some mouse strains. Two alternatively spliced exons (1a and 1b) encode the 5' untranslated region (5'UTR) of the murine locus 1. We have characterized the gene for the human interleukin-11 receptor alpha chain locus (hIL-11R alpha), examined its expression by Northern analysis and determined its chromosomal location by fluorescence in situ hybridization. The presence of exon(s) encoding the 5'UTR and mapping of transcription initiation sites was determined by reverse-transcriptase polymerase chain reaction and 5' rapid amplification of cDNA ends (5'RACE) techniques. The human locus spanned 10 kilobasepairs (kb) and consisted of 14 exons. Two alternatively spliced first exons (1a and 1b) encoding the 5'UTR were identified and shared 76 and 73% nucleotide identity with murine exons 1a and 1b. Multiple transcription start sites were demonstrated for human exon 1a. The promoter regions of both human exons 1a and 1b did not display a canonical TATA box. A predominant 1.8 kb transcript for the hIL-11R alpha was present in heart, brain, skeletal muscle, lymph nodes, thymus, appendix, pancreas and foetal liver. The hIL-11R alpha gene was localized to chromosome 9p13. In summary, the hIL-11R alpha gene was highly related to locus 1 of the murine gene and there was no evidence of a second hIL-11R alpha locus.
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PMID:The gene for the human interleukin-11 receptor alpha chain locus is highly homologous to the murine gene and contains alternatively spliced first exons. 925 Dec 43

We report the development of a reverse-transcriptase polymerase chain reaction assay that detects (in paraffin-embedded, formalin-fixed tissue) the SYT-SSXchimeric RNA transcript resulting from the t(X;18) of synovial sarcoma. The primers chosen detect both of the SSX1 and SSX2 partners, and the target sequence is small enough (87 base pairs) to be reliably detected in archival and variably processed consultation material. To demonstrate its usefulness, we applied it to 14 problematic cases, including spindle cell tumors of the thoracic region, of the neck, and of subcutaneous tissue. For instance, we show that, depending on the location, synovial sarcoma can mimic malignant solitary fibrous tumor, the spindle epithelial tumor with thymus-like differentiation, or skin adnexal tumors. Molecular detection of the SYT-SSX chimeric RNA should allow the reclassification of difficult cases in which the morphologic features overlap different entities or in which tumor nosology is still evolving.
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PMID:Detection of the SYT-SSX chimeric RNA of synovial sarcoma in paraffin-embedded tissue and its application in problematic cases. 955 26


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