Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.7.7.49 (reverse transcriptase)
 31,746 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The "stromal" or adherent cells of long-term murine Dexter explant bone marrow cultures provide the best in vitro model of the bone marrow microenvironment. Colony-stimulating factor-1 (CSF-1) is produced constitutively by these cells and is easily detected, but most investigators have not found constitutive production of the other hemolymphopoietic cytokines. We have previously reported the detection of granulocyte-macrophage-CSF (GM-CSF) in murine stromal cultures and its induction by the lectin Pokeweed mitogen. The present studies analyzing stromal cytokine messenger RNA (mRNA) production by standard Northern blot analysis show constitutive production of mRNAs for CSF-1, GM-CSF, granulocyte-CSF (G-CSF), c-kit ligand (KL), and interleukin-6 (IL-6), but not IL-3, IL-4, or IL-5 by 3-week irradiated or nonirradiated murine Dexter stromal cells. Exposure of stromal cells to Pokeweed mitogen or IL-1 16 hours before RNA harvest induces the messages for GM-CSF, G-CSF, KL, and IL-6, but not IL-3, IL-4, IL-5, or CSF-1. Polymerase chain reaction amplification of cDNA made with reverse transcriptase from stromal RNA using two separate sets of IL-3-specific primers shows the presence of IL-3 message in irradiated stromal cells, which is only detectable with this more sensitive technique. The factor-dependent cell lines FDC-P1 and 32D are supported by the stromal cells without the addition of exogenous growth factors, demonstrating a cytokine activity in these cultures that is inhibited by the addition of anti-IL-3 or anti-GM-CSF antibodies. These data indicate that murine Dexter stromal cells constitutively produce CSF-1, GM-CSF, G-CSF, IL-6, KL, and IL-3. This growth factor production could explain the support of granulocyte, macrophage, and megakaryocyte production and stem cell maintenance in Dexter-type long-term murine bone marrow cultures.
 ...
PMID:Biologic significance of constitutive and subliminal growth factor production by bone marrow stroma. 137 43

To examine the interaction between immature myeloid cells and stromal cells in the induction of granulocyte colony-stimulating factor (G-CSF) production, stromal cells of the MC3T3-G2/PA6 (PA6) murine cell line, which has preadipocyte characteristics and can support hematopoiesis, were cocultured with various myeloid cell lines and G-CSF mRNA expression was examined by Northern and reverse transcriptase-polymerase chain reaction analyses. A significant amount of G-CSF mRNA was induced by the culture of an interleukin-3/G-CSF-dependent murine myeloid leukemia cell line, NFS-60, on PA6 stromal cells for 16 hours. Using a G-CSF-dependent subline of DA-1 (DA-1N), the biologic activity of G-CSF was also detected in PA6/NFS-60 coculture supernatants, but not in the culture supernatant of PA6 or NFS-60 alone. Direct contact of NFS-60 cells with the PA6 stromal layer was essential for the induction of G-CSF mRNA, as indicated by the following observations: (1) NFS-60 cells efficiently adhered to PA6 cells; (2) medium conditioned by NFS-60 cells did not contain the activity to induce G-CSF mRNA in PA6 cells; and (3) induction of G-CSF mRNA was not observed when NFS-60 cells were separated from PA6 cells by a microporous membrane (0.45-microns pore size). Several other myeloid cell lines, including FDC-P2, 32Dcl3, WEHI-3, and DA-1, did not induce G-CSF mRNA expression after the coculture with PA6 cells, although significant numbers of these cells adhered to PA6 cells. Therefore, NFS-60 cells may express or overexpress a molecule that is involved in adhesion-mediated induction of G-CSF production.
 ...
PMID:Adhesion of NFS-60 myeloid leukemia cells to MC3T3-G2/PA6 stromal cells induces granulocyte colony-stimulating factor production. 751 14

Mechanisms of helper virus-induced growth factor-independence were examined in FDC-P1 cells and FDC-P1 cells expressing the erythropoietin receptor (FDER cells). Retroviral mutagenesis of FDC-P1 cells led to factor-independent (FI) colonies from which cell lines could readily be established; whereas control cells exhibited at least 20 to 40-fold lower rates of factor-independence. From 44 independent experiments using either FDC-P1 or FDER cells, 205 autonomous cell lines were obtained. Sixteen colonies displayed a novel ("satellite-inducing") appearance in agar and produced up to 4.1 x 10(5) U/mL granulocyte-macrophage colony-stimulating factor (GM-CSF) (some with altered GM-CSF transcript sizes) and/or interleukin-3 (IL-3). Retroviral mutagenesis of FDER cells increased the repertoire of autocrine growth factors now responsible for stimulating autocrine proliferation: 3% of FI cell lines produced erythropoietin (Epo) (0.5 U/mL). Unexpectedly, in every autonomous FDC-P1 cell line, reverse transcriptase-PCR demonstrated expression of a growth factor normally required for proliferation. Thus, a profound selection for cells able to produce growth factors as the mechanism for achieving autonomous proliferation was documented. The ectopic expression of a receptor lacking a cognate ligand ("orphan") followed by retroviral mutagenesis and selection for autocrine mutants may offer an effective method for identifying new ligands.
 ...
PMID:The cytokine receptor repertoire specifies autocrine growth factor production in factor-dependent cells. 772 Aug 17

Campomelic dysplasia (CMPD1) and autosomal XY sex reversal (SRA1) are caused by mutations in the SRY-related gene SOX9 on 17q. Unexpectedly, the 17q breakpoints in four CMPD1 translocation cases previously analyzed by us and others map 50 kb or more from SOX9. Here, we present clinical, cytogenetic, and molecular data from a new CMPD1/SRA1 patient with t(6;17)(q14;q24). Fluorescence in situ hybridization has shown that the 17q breakpoint in this case maps to the same region as the breakpoints in the other translocation cases, at least 130 kb from SOX9. Likewise, the breakpoints in two of the previously described cases also map more than 130 kb and, as shown by pulsed field gel electrophoresis analysis, at most 400 kb or 690 kb from SOX9. By using a SOX9 coding sequence polymorphism, expression of both SOX9 alleles has been demonstrated by the reverse transcriptase polymerase chain reaction in lymphoblastoid cells from one of the translocation cases.
 ...
PMID:Translocation breakpoints in three patients with campomelic dysplasia and autosomal sex reversal map more than 130 kb from SOX9. 856 51

We have previously reported that granulocyte-macrophage colony-stimulating factor (GM-CSF)- and interleukin-3 (IL-3)-dependent FDC-P1 cells undergo leukemic transformation when injected into sublethally irradiated DBA/2 mice. Transformation is related to aberrant activation of growth-regulatory genes by insertion of intracisternal A-particle (IAP) genomes. To elucidate the transformation process further, a subtracted cDNA library was constructed from a factor-independent leukemic FDC-P1 variant and the parental FDC-P1 cells. Screening for clones that were preferentially recognized by a total cDNA probe from the transformed cell line (in comparison to a similar probe from untransformed FDC-P1 cells) led to the isolation of 14 clones, of which six contained cDNA inserts encoding so-called B2 repeats, a class of short interspersed nucleotide elements. The expression of B2 repeats was significantly increased not only in the cell line from which the subtracted library was constructed, but also in all other leukemic FDC-P1 variants analyzed. B2 repeats can act as insertional mutagens and may have a role in the stabilization of certain oncogene and cytokine mRNAs. Interestingly, B2 repeats contain a 14-nucleotide region that is almost completely complementary to an AU-rich sequence in a region of the IAP mRNA encoding the enzyme reverse transcriptase. Although preliminary experiments to demonstrate stabilization of IAP mRNA by hybridization to B2 repeat sequences remained inconclusive, it is intriguing to speculate that B2 repeat sequences may have a causative role in the transformation process.
 ...
PMID:Indirect radiation leukemogenesis in DBA/2 mice: increased expression of B2 repeats in FDC-P1 cells transformed by intracisternal A-particle transposition. 954 Jul 58