GLORIA

GEOMAR Library Ocean Research Information Access

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Online Resource
    Online Resource
    Rockefeller University Press ; 1985
    In:  The Journal of cell biology Vol. 101, No. 6 ( 1985-12-01), p. 2274-2283
    In: The Journal of cell biology, Rockefeller University Press, Vol. 101, No. 6 ( 1985-12-01), p. 2274-2283
    Abstract: The subcellular localization of mouse mammary tumor virus (MMTV) glycoproteins was analyzed in infected and cloned rat hepatocarcinoma cells cultured with the MMTV transcriptional inducer dexamethasone. When reacted with protein A-coated erythrocytes in the presence of antisera specific for viral glycoproteins or with fluorescent antisera, only some of the cells acquired surface label. This diversity was dependent on cell anchorage to the substratum. In general, the more rounded, less adherent cells contained the MMTV glycoproteins on their surfaces, whereas the flatter, more adherent cells did not. After a change in adherence, a delay preceded complete remodeling of the plasma membranes. Fluorescent antibody studies of fixed cells and analyses of viral glycoprotein synthesis and shedding using L-[35S]methionine indicated that the different expression of MMTV glycoproteins in round versus flat cells is caused by a switch in posttranslational processing. In round cells, the MMTV-encoded precursor glycoprotein is proteolytically cleaved and then transported to plasma membranes as a complex of two subunits, the smaller being the membrane anchor. In flat adherent cells, the smaller subunit is rapidly degraded in an intracellular organelle and the larger is then secreted into the medium. As indicated by labeling of cells with 125I, the concentrations of several host-encoded plasma membrane components are also influenced by cell anchorage. We propose that this switch in cell surfaces and in secretions dependent upon cell-substratum attachments may be a common control mechanism important for embryogenesis, wound healing, and cancer.
    Type of Medium: Online Resource
    ISSN: 0021-9525 , 1540-8140
    RVK:
    Language: English
    Publisher: Rockefeller University Press
    Publication Date: 1985
    detail.hit.zdb_id: 1421310-2
    SSG: 12
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 2
    Online Resource
    Online Resource
    Elsevier BV ; 1982
    In:  Journal of Biological Chemistry Vol. 257, No. 23 ( 1982-12), p. 14023-14028
    In: Journal of Biological Chemistry, Elsevier BV, Vol. 257, No. 23 ( 1982-12), p. 14023-14028
    Type of Medium: Online Resource
    ISSN: 0021-9258
    Language: English
    Publisher: Elsevier BV
    Publication Date: 1982
    detail.hit.zdb_id: 2141744-1
    detail.hit.zdb_id: 1474604-9
    SSG: 12
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 3
    Online Resource
    Online Resource
    American Society for Microbiology ; 1976
    In:  Journal of Virology Vol. 19, No. 1 ( 1976-07), p. 118-125
    In: Journal of Virology, American Society for Microbiology, Vol. 19, No. 1 ( 1976-07), p. 118-125
    Abstract: The factors that control oncornavirus formation were analyzed in Friend leukemia cells that undergo hematopoiesis when treated with dimethyl sulfoxide. Suspension cultures of Ostertag FSD-1 cell line were found to enter a G or resting state at the end of their proliferative phase and to simultaneously cease producing helper and dependent components of Friend virus. Whereas the decline in virus production is at least 100-fold, rates of cellular RNA and protein synthesis are only slightly lower in resting than in growing cells. Both resting and growing cells contain similarly large concentrations of the viral proteins P(30) and P(12). Dimethyl sulfoxide induces hemoglobin synthesis in growing cells, but its effects on virus production appear to be indirect results of its action to inhibit cell growth and thus to delay entry of cells into the G resting state. Furthermore, variant cell lines were obtained with differing abilities to synthesize virus or hemoglobin. Some lines no longer produce infectious virus, although they all harbor murine leukemia virus genes which are expressed to varying extents. The major internal protein of these oncornaviruses, P(30), is synthesized in large amounts by all of the cell lines. These results suggest that Friend virus production is not coinduced with erythroid differentiation, as had been proposed, but rather is controlled by a cellular growth cycle.
    Type of Medium: Online Resource
    ISSN: 0022-538X , 1098-5514
    Language: English
    Publisher: American Society for Microbiology
    Publication Date: 1976
    detail.hit.zdb_id: 1495529-5
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 4
    Online Resource
    Online Resource
    Informa UK Limited ; 1984
    In:  Molecular and Cellular Biology Vol. 4, No. 5 ( 1984-05), p. 908-914
    In: Molecular and Cellular Biology, Informa UK Limited, Vol. 4, No. 5 ( 1984-05), p. 908-914
    Abstract: Friend spleen focus-forming virus shuts down its gene expression frequently (ca. 10(-3) per generation) in a cis-dominant hereditable fashion in various murine cells but much less frequently in rat cells (less than 10(-6) per generation). Thus, nonexpresser variants were isolated at high frequency from murine cell lines by immunoselection directed against virus-encoded cell surface glycoproteins and also simply by subcloning cells from lines which had been cultured for many generations. Studies of independently infected cell clones indicate that shutdown is a property of the cell line rather than of the specific proviral site. Nucleic acid blot analyses suggest that shutdown correlates with decreased transcription. Moreover, preliminary evidence indicates that other murine retroviruses also shut down frequently in murine but not in rat cells and that shutdown of replication-competent murine leukemia viruses with accompanying loss in interference to superinfection may be the rate-limiting reaction enabling cells to acquire multiple proviruses in their chromosomes. High-frequency shutdown in vivo would have important pathological consequences.
    Type of Medium: Online Resource
    ISSN: 0270-7306 , 1098-5549
    RVK:
    Language: English
    Publisher: Informa UK Limited
    Publication Date: 1984
    detail.hit.zdb_id: 1474919-1
    SSG: 12
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 5
    Online Resource
    Online Resource
    Proceedings of the National Academy of Sciences ; 1980
    In:  Proceedings of the National Academy of Sciences Vol. 77, No. 1 ( 1980-01), p. 57-61
    In: Proceedings of the National Academy of Sciences, Proceedings of the National Academy of Sciences, Vol. 77, No. 1 ( 1980-01), p. 57-61
    Abstract: We have described a heterogeneously processed glycoprotein with an apparent molecular weight of 55,000 (gp55) that is encoded by the Friend spleen focus-forming virus, an acute erythroleukemia virus [Dresler, S., Ruta, M., Murray, M.J. & Kabat, D. (1976) J. Virol. 30, 564-573]. Several lines of evidence suggest that a small proportion of the gp55 in infected cells is located on the surface membranes. First, different nonproducer cell lines infected with cloned Friend spleen focus-forming virus were efficiently killed in the presence of complement by cytotoxic antisera that react with gp55. Furthermore, a clone of cells selected for resistance to the cytotoxic antibody synthesized an altered intracellular form of gp55. This immunoselection procedure appears to also be useful for isolating glycoprotein mutants of other RNA tumor viruses. Analysis of cell surface proteins labeled with [125I] iodine supported the idea that gp55 occurs on the plasma membranes. However, the cell surface gp55 had more highly processed oligosaccharides than the majority of the gp55, which occurs within the infected cells. In addition, we have found that leukemia cells from mice infected with the erythroleukemic Rauscher virus complex contain a membrane glycoprotein that appears similar to the gp55 encoded by Friend spleen focus-forming virus. The encoding of similar glycoproteins by independently isolated acute erythroleukemia viruses suggests that these glycoproteins may be important in leukemogenesis.
    Type of Medium: Online Resource
    ISSN: 0027-8424 , 1091-6490
    RVK:
    RVK:
    Language: English
    Publisher: Proceedings of the National Academy of Sciences
    Publication Date: 1980
    detail.hit.zdb_id: 209104-5
    detail.hit.zdb_id: 1461794-8
    SSG: 11
    SSG: 12
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...