scholarly journals Comparison of the relative importance of tyrosine-specific vinculin phosphorylation and the loss of surface-associated fibronectin in the morphology of cells transformed by Rous sarcoma virus

1986 ◽  
Vol 82 (1) ◽  
pp. 129-142
Author(s):  
S. Kellie ◽  
B. Patel ◽  
A. Mitchell ◽  
D.R. Critchley ◽  
N.M. Wigglesworth ◽  
...  
Keyword(s):  
Rous Sarcoma Virus ◽  
Relative Importance ◽  
Plasma Fibronectin ◽  
Short Term ◽  
Normal Morphology ◽  
Rous Sarcoma ◽  
Microfilament Bundles ◽  
Sarcoma Virus ◽  
Adhesion Plaques

We have investigated the relative importance of tyrosine-specific phosphorylation of vinculin and the loss of surface-associated fibronectin in the maintenance of the rounded morphology characteristic of chick embryo fibroblasts (CEF) transformed by Rous sarcoma virus (RSV). To address this question we have examined the interaction of CEF and RSV-CEF in vitro with exogenously added fibronectin in both 3-day culture experiments and short-term, 3-h spreading experiments. We report that the addition of human plasma fibronectin to cultures of RSV-CEF results in the restoration of a near-normal morphology, as has been described previously, with the added fibronectin incorporated into an extracellular matrix. However, the phosphotyrosine content of vinculin in these cells was unchanged from that of control, untreated RSV-CEF despite the change in morphology. In short-term spreading experiments RSV-CEF were unable to adopt a fully spread morphology on fibronectin substrates, with defects in the formation of adhesion plaques and microfilament bundles compared with untransformed CEF. pp60v-src was present in the newly formed adhesion plaques of RSV-CEF spreading on fibronectin substrates. The relevance of these results to the maintenance of the transformed phenotype is discussed.

Functional domains of the pp60v-src protein as revealed by analysis of temperature-sensitive Rous sarcoma virus mutants

1984 ◽  
Vol 4 (8) ◽  
pp. 1508-1514
Author(s):  
A W Stoker ◽  
P J Enrietto ◽  
J A Wyke
Keyword(s):  
Rous Sarcoma Virus ◽  
Kinase Activity ◽  
Temperature Sensitive ◽  
Tyrosine Kinase Activity ◽  
Rous Sarcoma ◽  
Heat Labile ◽  
Src Gene ◽  
Sarcoma Virus

Four temperature-sensitive (ts) Rous sarcoma virus src gene mutants with lesions in different parts of the gene represent three classes of alteration in pp60src. These classes are composed of mutants with (i) heat-labile protein kinase activities both in vitro and in vivo (tsLA27 and tsLA29), (ii) heat-labile kinases in vivo but not in vitro (tsLA33), and (iii) neither in vivo nor in vitro heat-labile kinases (tsLA32). The latter class indicates the existence of structural or functional pp60src domains that are required for transformation but do not grossly affect tyrosine kinase activity.

Phenotypic change from transformed to normal induced by benzoquinonoid ansamycins accompanies inactivation of p60src in rat kidney cells infected with Rous sarcoma virus

1986 ◽  
Vol 6 (6) ◽  
pp. 2198-2206
Author(s):  
Y Uehara ◽  
M Hori ◽  
T Takeuchi ◽  
H Umezawa
Keyword(s):  
Immune Complex ◽  
Rous Sarcoma Virus ◽  
Morphological Changes ◽  
Rat Kidney ◽  
Phenotypic Change ◽  
Permissive Temperature ◽  
Rous Sarcoma ◽  
Cell Extracts ◽  
Sarcoma Virus

Three benzenoid ansamycin antibiotics (herbimycin, macbecin, and geldanamycin) were found to reduce the intracellular phosphorylation of p60src at a permissive temperature (33 degrees C) in a rat kidney cell line infected with a temperature-sensitive mutant of Rous sarcoma virus. This effect was accompanied by morphological changes from the transformed to the normal phenotype. The filamentous staining pattern of actin fibers was observed in the cells treated with these antibiotics at 33 degrees C. Removal of the antibiotics allowed the cells to revert to the transformed morphology. Ansamitocin, another benzenoid ansamycin, and naphthalenoid ansamycins such as streptovaricin and rifamycins did not show this effect. Pulse-labeling of the antibiotic-treated cultures with 32Pi showed a marked reduction of 32P radioactivity incorporated into p60src. A parallel experiment with [35S]methionine showed that synthesis of p60src was slightly inhibited. The immune complex prepared by mixing the herbimycin-treated cell extracts with antibody against p60src was inactive in vitro in phosphorylating the complex itself. On the contrary, the immune complex derived from untreated cells was active in vitro even in the presence of the antibiotics. These results suggest that benzoquinonoid ansamycins have no direct effect on src kinase but destroy its intracellular environment, resulting in an irreversible alteration of p60src and loss of catalytic activity.

scholarly journals COMPARATIVE STUDIES IN ROUS SARCOMA WITH VIRUS, TUMOR CELLS, AND CHICK EMBRYO CELLS TRANSFORMED IN VITRO BY VIRUS

1962 ◽  
Vol 115 (1) ◽  
pp. 245-251 ◽  
Author(s):  
Robert M. Dougherty ◽  
Herbert R. Morgan
Keyword(s):  
Chick Embryo ◽  
Tumor Cells ◽  
Comparative Studies ◽  
Rous Sarcoma Virus ◽  
Rous Sarcoma ◽  
Transformed Fibroblasts ◽  
Embryo Cells ◽  
Sarcoma Virus

Chick embryo fibroblasts infected in vitro with Rous sarcoma virus have properties similar to tumor cells when injected into virus-immune chickens. When such virus-transformed fibroblasts are injected into normal chickens, they apparently participate in the production of tumors independent of their release of virus and are thus apparently malignant in vivo.

Long-term cultures of chick embryo fibroblasts transformed by the Schmidt–Ruppin strain (D) of Rous sarcoma virus

1976 ◽  
Vol 22 (10) ◽  
pp. 1474-1479
Author(s):  
Lorraine Leblond-Larouche ◽  
Réjean Morais
Keyword(s):  
Chick Embryo ◽  
Rous Sarcoma Virus ◽  
Rous Sarcoma ◽  
Viable Cells ◽  
Deficient Medium ◽  
Sarcoma Virus ◽  
Embryo Fibroblasts ◽  
Roller Cultures

Attempts have been made to keep in vitro, for extended periods of time, cultures of chick embryo fibroblasts transformed by the Schmidt–Ruppin strain of Rous sarcoma virus, subgroup D. Roller cultures of transformed chick cells kept in serum-deficient medium can be maintained without subcultivation for up to 6 months. The confluent cultures continuously release viruses and viable tumor cells into the medium. The released cells can be plated and have characteristics of growth and morphology which are relatively stable with time until the culture degenerates. Cells released at later stages of the culture produced substantially more viruses than those released earlier, suggesting that cell selection or differentiation occurs during long-term cultivation in low serum concentration. Long-term cultures of untransformed chick embryo fibroblasts can also be maintained in the same way. The release of viable cells by these confluent cultures, however, is negligible.

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