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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We have used two kinds of vectors to express a cDNA of human tissue plasminogen activator (t-PA) in mammalian cells. In one case, cDNAs inserted into vectors based on bovine papilloma virus were introduced into cultured murine cells and cell lines were established that efficiently and continuously secrete enzymatically active t-PA into the medium. Second, the t-PA gene was used to replace the sequences of the simian virus (SV40) genome that code for the viral coat proteins. Virus stocks were generated and used to infect a stable line of cultured simian cells. During the resulting lytic infection, expression of the t-PA gene is governed by the potent SV40 late promoter and enzymatically active t-PA accumulates rapidly in the medium. We have used these two vector systems to analyze the biosynthesis and transport of recombinant t-PA and to compare its properties with those of "natural" t-PA secreted by the Bowes line of human melanoma cells. t-PA secreted from all three sources is identical in specific activity (approximately 20,000 units/mg) despite differences in patterns of terminal glycosylation. Furthermore, non-glycosylated t-PA synthesized in the presence of tunicamycin was secreted efficiently and was indistinguishable in specific activity from glycosylated t-PAs.
Mol Biol Med 1986 Dec
PMID:Expression of human tissue-type plasminogen activator from lytic viral vectors and in established cell lines. 303 88

Specific keratin cDNA probes and monospecific antikeratin antisera were used to analyze mouse epidermis and epidermal tumors for the expression of a type I 47-kDa keratin, K13, normally associated with terminal differentiation of internal stratified epithelia. We demonstrated that this keratin was virtually absent from the entire body epidermis at various stages of development. Also, it was not detected in various forms of acute and chronic epidermal hyperproliferation or in epidermal cells cultured under conditions that favored either cell proliferation or in vitro differentiation. In contrast, K13 was consistently expressed in squamous cell carcinomas of the skin induced by 7,12-dimethylbenz[a]anthracene and 12-O-tetradecanoylphorbol-13-acetate (TPA), whereas papillomas obtained by the same two-stage protocol were distinctly heterogeneous with regard to the expression of this keratin. These findings were true for two different strains of mice (NMRI and Sencar). Papillomas collected from Sencar mice after 12 wk or from NMRI mice after 15 wk of promotion with TPA were either negative for K13 or elicited variable amounts of this keratin. In all cases of positive expression of K13 in tumors, as in normal stratified internal epithelia, both the keratin protein and its mRNA invariably occurred in the differentiating cell compartments. In contrast to what we found in internal stratified epithelia, however, K13 was expressed without its commonly encountered type II 57-kDa partner, K4. Papillomas negative for the K13 protein were also devoid of K13 transcripts. This indicates that the aberrant K13 expression in tumors is regulated at the level of transcription. Our results suggest that K13 may provide a marker for malignant conversion in the mouse two-stage skin carcinogenesis model and may be especially suited for studies of gene expression regulation.
Mol Carcinog 1988
PMID:Aberrant expression during two-stage mouse skin carcinogenesis of a type I 47-kDa keratin, K13, normally associated with terminal differentiation of internal stratified epithelia. 307 54

A bovine papilloma virus-derived vector was used to direct the high level expression in mouse C127 cells of three different cDNAs encoding the human interleukin-2 receptor. These were: the previously described cDNA clone isolated from the T-cell lymphoma, HUT-102; a cDNA clone isolated from mitogen-activated, normal peripheral blood T cells; and an altered version of the HUT-102 receptor in which Ser247, believed to be the site of protein kinase C-mediated phosphorylation, has been changed to an Ala residue. Fluorescence-activated cell-sorting using a monoclonal antibody directed against the human IL-2 receptor was used to derive stable lines of C127 cells expressing from 2-6 X 10(6) IL-2 binding sites per cell. However, all of these receptors bound IL-2 with low affinity.
Mol Immunol 1986 Sep
PMID:High level stable expression of human interleukin-2 receptors in mouse cells generates only low affinity interleukin-2 binding sites. 309 20

We have developed a highly efficient system for producing hepatitis B virus surface antigen in cultured mammalian cells. This system utilizes a recombinant bovine papilloma virus in which the hepatitis surface antigen coding sequences are inserted into the 5' untranslated region of the mouse metallothionein-I gene. Mouse fibroblasts stably transformed with this molecule produce surface antigen at levels as high as 10 mg/L/24 h and can be maintained in continuous culture for up to 85 days.
J Mol Appl Genet 1984
PMID:Efficient production of hepatitis B surface antigen using a bovine papilloma virus-metallothionein vector. 609 May 67

A novel eucaryotic vector derived from the transforming region of bovine papilloma virus was established and demonstrated to be highly effective for introducing foreign genes into animal cells. The foreign deoxyribonucleic acid (DNA) is replicated and actively transcribed as an episome, and the transcripts are translated into an authentic gene product. We have constructed a DNA hybrid molecule, BPV69T-rI1, containing the transforming region of bovine papilloma virus DNA and the rat preproinsulin gene I (rI1), and used it to transform susceptible mouse cells. DNA hybridization analysis has demonstrated the presence of multiple unintegrated copies of hybrid DNA molecules, with the bovine papilloma virus 1 DNA segment and the rI1 gene covalently linked in selected transformed cell lines. S1 nuclease analysis revealed the presence of a correctly spliced coding segment of the preproinsulin transcript similar or identical in its electrophoretic mobility to that of messenger ribonucleic acid produced in rat insulinoma cells. Significant levels of a protein immunoreactive with anti-insulin serum were detected by radioimmunoassay in the culture medium of transformed cells. Immunoprecipitation analysis in conjunction with competitive binding to bovine proinsulin established the identity of the protein as that of rat proinsulin.
Mol Cell Biol 1981 Jun
PMID:Bovine papilloma virus deoxyribonucleic acid: a novel eucaryotic cloning vector. 610 Sep 67

The 7, 12-dimethylbenzanthracene-induced skin papilloma of the mouse and the 3-methylcholanthrene-induced hyperplasia and metaplasia in prostate organ cultures were studied by electron microscopy. The two types of tissue both showed a reversal of hyperplasia and metaplasia when treated with retinoids (= vitamin A and analogs). This reversal was reached by means that are quite characteristic for a given type of tissue. In the skin, DNA-synthetic activity was not influenced by retinoid treatment. There was however, considerable necrosis and an impressive mucous metaplasia. The latter might be at least partly responsible for the cell loss, probably through a loss of anchorage in the prickle-cell layer. In the prostate, no mucous metaplasia was observed, but there was an important depression of DNA-synthetic activity. The secretory apparatus reappeared together with the microvilli, possibly induced by the slowing down of cell division.
Virchows Arch B Cell Pathol Incl Mol Pathol 1980
PMID:Ultrastructural analysis of the retinoid-induced reversal of epithelial hyperplasia and metaplasia. 611 Feb 69

Endocrine cells are a normal constituent of the prostate gland, prostatic urethra and urinary bladder mucosa. Positive results using immunohistochemical technics were obtained only with antiserotonin antibodies. In normal tissues, there was a close similarity between the distribution of argyrophilic cells (Grimelius) and serotonin-storing cells. Some striking features were the patchy distribution of endocrine cells, the presence of slender cytoplasmic processes occasionally reaching the luminal surface and the paucity of specialized cells in bladder mucosa. It is unlikely that endocrine cells participate in conventional neoplasms of prostate and bladder. Exceptions are lobular hyperplasia, certain adeno-carcinomas of prostate and inverted papilloma of bladder. An ultrastructural study permitted the distinction of two types of endocrine cells characterized by a different morphology of their granules. Another relevant finding was the presence of serotonin-storing cells in Brenner tumors. The latter observation emphasizes the close similarity between this neoplastic epithelium and urothelium. This implies that endocrine cells may be of mesodermal derivation.
Virchows Arch B Cell Pathol Incl Mol Pathol 1983
PMID:Endocrine cells in the prostate gland, urothelium and Brenner tumors. Immunohistological and ultrastructural studies. 613 89

We have studied the ultrastructure of glycocalyx at the luminal surface of normal and diseased urothelium from humans and rats with ruthenium red staining. A correlation between the thickness and staining intensity of the glycocalyx and the surface topography of the luminal surface was observed. An intensely stained thick glycocalyx was associated with prominent surface microvilli seen in the following conditions in humans: some control urothelium, inverted papilloma, well and moderately differentiated transitional cell carcinomas and mucin producing adenocarcinomas. These changes were also present in rats with FANFT-induced preneoplastic and neoplastic changes. A thin glycocalyx was associated with a scalloped luminal surface containing asymmetric unit membrane plaques and was found in some control humans urothelium and in normal rat urothelium. A thin glycocalyx was also associated with the relatively smooth surface seen in poorly differentiated transitional cell carcinomas as well as in some mucin producing adenocarcinomas. We suggest that urothelial glycocalyx, as demonstrated by ruthenium red staining, correlates with the luminal surface topography rather than specific pathological conditions of the bladder.
Virchows Arch B Cell Pathol Incl Mol Pathol 1983
PMID:Cell surface coat of human and rat bladder urothelium. I. Ruthenium-red studies in non-neoplastic and neoplastic cells. 619 Mar 6

Cloned bovine papilloma virus (BPV) DNA induces cellular transformation when introduced into mouse cells growing in culture; the transferred viral DNA replicates as an extrachromosomal, closed circular element. BPV DNA is therefore an inviting replicon to construct a "shuttle" vector that can replicate in both mammalian cells and E. coli. Although BPV DNA devoid of bacterial plasmid sequences has been successfully employed to reintroduce cloned genes into rodent cells, construction of a true shuttle plasmid has been hampered by a disruptive influence of bacterial plasmid sequences that appear to block cellular transformation when included on the transferred molecule. We constructed a molecule, pGP, containing the transforming region of the BPV genome, the rat growth hormone gene, and bacterial plasmid pBR 327, and have found unexpectedly that the intact molecule can induce cellular transformation of mouse cells at high efficiency despite the presence of bacterial sequences in the transferred plasmid. A similar plasmid without the growth hormone segment does not transform mouse cells. The pGP molecule replicates as a stable plasmid in both mouse cells, where there are 30 to 80 monomer episomes per cell, and E. coli, and may be shuttled back and forth unaltered between the two kinds of cells. The growth hormone gene is transcribed in the mouse cells and gives rise to a transcript that is longer than authentic rat growth hormone mRNA and does not appear to be regulated by glucocorticoids. When pGP is cotransferred into mouse L-cells with herpes simplex virus tk gene, it appears to integrate, and free monomer episomes are not observed.
J Mol Appl Genet 1982
PMID:A plasmid that replicates in both mouse and E. coli cells. 629 55

A 1.6-kilobase DNA segment of the genomic human interferon beta 1 (IF-beta 1) gene was inserted into each of two possible orientations at the single HindIII site of a recombinant plasmid pBPV69T, consisting of the 69% transforming region of the bovine papilloma virus type 1 (BPV-1) and a modified SalI-SalI fragment of plasmid pBR322. After cleavage of the pBR322 sequences from this recombinant, BPV69T-IF-beta 1 hybrid DNAs were transfected onto C127 mouse cells by the standard calcium precipitation technique. Mouse cells transformed by this hybrid DNA produced low levels of human IF-beta 1 constitutively and responded to induction with either inactivated Newcastle disease virus or polyriboinosinic acid-polyribocytidylic acid. The BPV69T-IF-beta 1 hybrid DNA was nonintegrated in the transformed mouse cells but had acquired DNA sequences as a result of the transfection. Accurate transcripts of the IF-beta 1 mRNA were detected in cells only after induction. When the IF-beta 1 gene was oriented in the plasmid in the same direction of transcription as the BPV-1 genome, transcription was promoted from within the BPV-1 sequences. These results indicate that the regulatory sequences responsible for the inducible expression of the human IF-beta 1 gene are present in the 1.6-kilobase genomic segment and that these sequences can function in a free extrachromosomal state linked to BPV-1 sequences.
Mol Cell Biol 1983 Feb
PMID:Inducible expression of the human interferon beta 1 gene linked to a bovine papilloma virus DNA vector and maintained extrachromosomally in mouse cells. 630 Jun 59


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