scholarly journals The response of chicken embryo dermal fibroblasts to cytochalasin B is altered by Rous sarcoma virus-induced cell transformation.

1982 ◽  
Vol 2 (3) ◽  
pp. 320-330 ◽  
Author(s):  
A S Menko ◽  
J Croop ◽  
Y Toyama ◽  
H Holtzer ◽  
D Boettiger
Keyword(s):  
Rous Sarcoma Virus ◽  
Chicken Embryo ◽  
Cytochalasin B ◽  
Dendritic Morphology ◽  
Dermal Fibroblasts ◽  
Transformed Cells ◽  
Temperature Sensitive ◽  
High Concentration ◽  
Rous Sarcoma ◽  
Sarcoma Virus

The drug cytochalasin B (CB), which disrupts the cellular microfilament network, allows the identification of as yet unclassified structural differences between normal and Rous sarcoma virus-transformed chicken embryo fibroblasts. When exposed to CB, normal chick fibroblasts attain an arborized or dendritic morphology. This results as the cytoplasm collapses upon the remaining structural and adhesive components of the cell. Rous sarcoma virus-transformed cells did not form or maintain these dendritic-like processes in the presence of CB and, as a result, rounded up but still remained attached to the substrate. With a temperature-sensitive mutant of Rous sarcoma virus, LA24A, it was possible to show that these effects are completely reversible and dependent on the expression of pp60src. The cytoskeleton in these CB-treated cells was examined by both immunofluorescence and electron microscopy. After exposure to CB, the microfilaments were found to be disrupted similarly throughout both the transformed and the nontransformed cells. In the nontransformed cells arborized by exposure to CB, the extended processes were found to contain intermediate filaments in an unusually high concentration and degree of organization. The distribution of these filaments in the central body of the arborized cells was random. This lower concentration and random distribution was similar to that seen throughout the transformed cells rounded up by exposure to CB. The failure of these transformed cells to arborize in CB indicates that the structural component(s) which is necessary for the formation or maintenance or both of the arborized state is altered by the expression of pp60src.

The response of chicken embryo dermal fibroblasts to cytochalasin B is altered by Rous sarcoma virus-induced cell transformation

1982 ◽  
Vol 2 (3) ◽  
pp. 320-330
Author(s):  
A S Menko ◽  
J Croop ◽  
Y Toyama ◽  
H Holtzer ◽  
D Boettiger
Keyword(s):  
Rous Sarcoma Virus ◽  
Chicken Embryo ◽  
Cytochalasin B ◽  
Dendritic Morphology ◽  
Dermal Fibroblasts ◽  
Transformed Cells ◽  
Temperature Sensitive ◽  
High Concentration ◽  
Rous Sarcoma ◽  
Sarcoma Virus

The drug cytochalasin B (CB), which disrupts the cellular microfilament network, allows the identification of as yet unclassified structural differences between normal and Rous sarcoma virus-transformed chicken embryo fibroblasts. When exposed to CB, normal chick fibroblasts attain an arborized or dendritic morphology. This results as the cytoplasm collapses upon the remaining structural and adhesive components of the cell. Rous sarcoma virus-transformed cells did not form or maintain these dendritic-like processes in the presence of CB and, as a result, rounded up but still remained attached to the substrate. With a temperature-sensitive mutant of Rous sarcoma virus, LA24A, it was possible to show that these effects are completely reversible and dependent on the expression of pp60src. The cytoskeleton in these CB-treated cells was examined by both immunofluorescence and electron microscopy. After exposure to CB, the microfilaments were found to be disrupted similarly throughout both the transformed and the nontransformed cells. In the nontransformed cells arborized by exposure to CB, the extended processes were found to contain intermediate filaments in an unusually high concentration and degree of organization. The distribution of these filaments in the central body of the arborized cells was random. This lower concentration and random distribution was similar to that seen throughout the transformed cells rounded up by exposure to CB. The failure of these transformed cells to arborize in CB indicates that the structural component(s) which is necessary for the formation or maintenance or both of the arborized state is altered by the expression of pp60src.

Altered cell spreading in cytochalasin B: a possible role for intermediate filaments

1983 ◽  
Vol 3 (1) ◽  
pp. 113-125
Author(s):  
A S Menko ◽  
Y Toyama ◽  
D Boettiger ◽  
H Holtzer
Keyword(s):  
Intermediate Filaments ◽  
Rous Sarcoma Virus ◽  
Cytochalasin B ◽  
Dermal Fibroblasts ◽  
Transformed Cells ◽  
Temperature Sensitive ◽  
Permissive Temperature ◽  
Rous Sarcoma ◽  
Microfilament Bundles ◽  
Sarcoma Virus

Trypsinized chicken embryo dermal fibroblasts plated in the presence of cytochalasin B (CB) quickly attached to the substrate and within 24 h obtained an arborized morphology. This morphology is the result of the pushing out of pseudopodial processes along the substrate from the round central cell body. There were no microfilament bundles in the processes of these cells plated in the presence of CB; however, the processes were packed with highly oriented, parallel-aligned intermediate filaments. Only a few scattered microtubules were seen in these processes. These results demonstrated that in CB, cells are capable of a form of movement, i.e., the extension of pseudopodial processes, without the presence of the microfilament structures usually associated with extensions of the cytoplasm and pseudopodial movements. We also found that arborization did not depend on fibronectin since cells plated in CB did not have fibronectin fibers associated with the processes. Chicken fibroblasts transformed with tsLA24A, a Rous sarcoma virus which is temperature sensitive for pp60src, formed arborized cells with properties similar to those of uninfected fibroblasts when plated in the presence of CB at the nonpermissive temperature (41 degrees C). At the permissive temperature for transformation (36 degrees C), the cells attached to the substrate but remained round. These round cells were not only deficient in microfilament bundles but also lacked the highly organized intermediate filaments found in the processes of the arborized cells at 41 degrees C. Although both microfilament bundles and the fibronectin matrix were decreased after transformation with Rous sarcoma virus, neither was involved in the formation of processes in normal cells plated in CB. Therefore, the inability of the transformed cells to form or maintain processes in CB must be the result of another structural alteration in the transformed cells, such as that of the intermediate filaments.

scholarly journals Altered cell spreading in cytochalasin B: a possible role for intermediate filaments.

1983 ◽  
Vol 3 (1) ◽  
pp. 113-125 ◽  
Author(s):  
A S Menko ◽  
Y Toyama ◽  
D Boettiger ◽  
H Holtzer
Keyword(s):  
Intermediate Filaments ◽  
Rous Sarcoma Virus ◽  
Cytochalasin B ◽  
Dermal Fibroblasts ◽  
Transformed Cells ◽  
Temperature Sensitive ◽  
Permissive Temperature ◽  
Rous Sarcoma ◽  
Microfilament Bundles ◽  
Sarcoma Virus

Trypsinized chicken embryo dermal fibroblasts plated in the presence of cytochalasin B (CB) quickly attached to the substrate and within 24 h obtained an arborized morphology. This morphology is the result of the pushing out of pseudopodial processes along the substrate from the round central cell body. There were no microfilament bundles in the processes of these cells plated in the presence of CB; however, the processes were packed with highly oriented, parallel-aligned intermediate filaments. Only a few scattered microtubules were seen in these processes. These results demonstrated that in CB, cells are capable of a form of movement, i.e., the extension of pseudopodial processes, without the presence of the microfilament structures usually associated with extensions of the cytoplasm and pseudopodial movements. We also found that arborization did not depend on fibronectin since cells plated in CB did not have fibronectin fibers associated with the processes. Chicken fibroblasts transformed with tsLA24A, a Rous sarcoma virus which is temperature sensitive for pp60src, formed arborized cells with properties similar to those of uninfected fibroblasts when plated in the presence of CB at the nonpermissive temperature (41 degrees C). At the permissive temperature for transformation (36 degrees C), the cells attached to the substrate but remained round. These round cells were not only deficient in microfilament bundles but also lacked the highly organized intermediate filaments found in the processes of the arborized cells at 41 degrees C. Although both microfilament bundles and the fibronectin matrix were decreased after transformation with Rous sarcoma virus, neither was involved in the formation of processes in normal cells plated in CB. Therefore, the inability of the transformed cells to form or maintain processes in CB must be the result of another structural alteration in the transformed cells, such as that of the intermediate filaments.

scholarly journals Tropomyosin isoforms in chicken embryo fibroblasts: purification, characterization, and changes in Rous sarcoma virus-transformed cells.

1985 ◽  
Vol 100 (3) ◽  
pp. 692-703 ◽  
Author(s):  
J J Lin ◽  
D M Helfman ◽  
S H Hughes ◽  
C S Chou
Keyword(s):  
Rous Sarcoma Virus ◽  
Chicken Embryo ◽  
Actin Binding ◽  
Transformed Cells ◽  
Two Dimensional ◽  
Tropomyosin Isoforms ◽  
Rous Sarcoma ◽  
Sarcoma Virus ◽  
Embryo Fibroblasts ◽  
Chicken Embryo Fibroblasts

Seven polypeptides (a, b, c, 1, 2, 3a, and 3b) have been previously identified as tropomyosin isoforms in chicken embryo fibroblasts (CEF) (Lin, J. J.-C., Matsumura, F., and Yamashiro-Matsumura, S., 1984, J. Cell. Biol., 98:116-127). Spots a and c had identical mobility on two-dimensional gels with the slow-migrating and fast-migrating components, respectively, of chicken gizzard tropomyosin. However, the remaining isoforms of CEF tropomyosin were distinct from chicken skeletal and cardiac tropomyosins on two-dimensional gels. The mixture of CEF tropomyosin has been isolated by the combination of Triton/glycerol extraction of monolayer cells, heat treatment, and ammonium sulfate fractionation. The yield of tropomyosin was estimated to be 1.4% of total CEF proteins. The identical set of tropomyosin isoforms could be found in the antitropomyosin immunoprecipitates after the cell-free translation products of total poly(A)+ RNAs isolated from CEF cells. This suggested that at least seven mRNAs coding for these tropomyosin isoforms existed in the cell. Purified tropomyosins (particularly 1, 2, and 3) showed different actin-binding abilities in the presence of 100 mM KCl and no divalent cation. Under this condition, the binding of tropomyosin 3 (3a + 3b) to actin filaments was significantly weaker than that of tropomyosin 1 or 2. CEF tropomyosin 1, and probably 3, could be cross-linked to form homodimers by treatment with 5,5'-dithiobis-(2-nitrobenzoate), whereas tropomyosin a and c formed a heterodimer. These dimer species may reflect the in vivo assembly of tropomyosin isoforms, since dimer formation occurred not only with purified tropomyosin but also with microfilament-associated tropomyosin. The expression of these tropomyosin isoforms in Rous sarcoma virus-transformed CEF cells has also been investigated. In agreement with the previous report by Hendricks and Weintraub (Proc. Natl. Acad. Sci. USA., 78:5633-5637), we found that major tropomyosin 1 was greatly reduced in transformed cells. We have also found that the relative amounts of tropomyosin 3a and 3b were increased in both the total cell lysate and the microfilament fraction of transformed cells. Because of the different actin-binding properties observed for CEF tropomyosins, changes in the expression of these isoforms may, in part, be responsible for the reduction of actin cables and the alteration of cell shape found in transformed cells.

scholarly journals Identification of Phosphotyrosine-Containing Proteins in Untransformed and Rous Sarcoma Virus-Transformed Chicken Embryo Fibroblasts

1982 ◽  
Vol 2 (6) ◽  
pp. 653-665 ◽  
Author(s):  
Ricardo Martinez ◽  
Kenji D. Nakamura ◽  
Michael J. Weber
Keyword(s):  
Protein Kinases ◽  
Rous Sarcoma Virus ◽  
Chicken Embryo ◽  
Cellular Protein ◽  
Transformed Cells ◽  
Phosphoamino Acid ◽  
Rous Sarcoma ◽  
Sarcoma Virus ◽  
Embryo Fibroblasts ◽  
Chicken Embryo Fibroblasts

Phosphorylation on tyrosine residues mediated by pp60srcappears to be a primary biochemical event leading to the establishment of the transformed phenotype in Rous sarcoma virus (RSV)-infected cells. To identify the cellular proteins that undergo tyrosine phosphorylation during transformation, a32P-labeled RSV-transformed chicken embryo cell extract was analyzed by electrophoresis on a polyacrylamide gel. After slicing the gel into approximately 60 slices, phosphoamino acid analyses were carried out on the protein recovered from each gel slice. Phosphotyrosine was found in every gel slice, with two major peaks of this phosphoamino acid aroundMr's of 59 and 36 kilodaltons. When the same analysis was performed with cells infected with a transformation-defectivesrcdeletion mutant of RSV (tdNY101), significant and reproducible peaks of phosphotyrosine were found in only 2 of 60 gel slices. These gel slices corresponded toMr's of 42 and 40 kilodaltons. Identical results were obtained with normal uninfected chicken embryo fibroblasts. We conclude from these observations that pp60srcor the combined action of pp60srcand pp60src-activated cellular protein kinases cause the tyrosine-specific phosphorylation of a very large number of cellular polypeptides in RSV-transformed cells. In addition, untransformed cells appear to possess one or more active tyrosine-specific protein kinases which are responsible for the phosphorylation of a limited number of proteins. These proteins are different from the major phosphotyrosine-containing proteins of the transformed cells.

Transformation of chicken embryo retinal melanoblasts by a temperature-sensitive mutant of rous sarcoma virus

Cell ◽  
1977 ◽  
Vol 11 (4) ◽  
pp. 881-890 ◽  
Author(s):  
Kate Roby ◽  
John Brumbaugh ◽  
Judy Biehl ◽  
Howard Holtzer ◽  
David Boettiger
Keyword(s):  
Rous Sarcoma Virus ◽  
Chicken Embryo ◽  
Temperature Sensitive ◽  
Sensitive Mutant ◽  
Temperature Sensitive Mutant ◽  
Rous Sarcoma ◽  
Sarcoma Virus

78-kilodalton glucose-regulated protein is induced in Rous sarcoma virus-transformed cells independently of glucose deprivation

1988 ◽  
Vol 8 (7) ◽  
pp. 2675-2680
Author(s):  
M Y Stoeckle ◽  
S Sugano ◽  
A Hampe ◽  
A Vashistha ◽  
D Pellman ◽  
...  
Keyword(s):  
Rous Sarcoma Virus ◽  
Glucose Deprivation ◽  
Transformed Cells ◽  
Nucleotide Sequence Analysis ◽  
Temperature Sensitive ◽  
Sensitive Mutant ◽  
Temperature Sensitive Mutant ◽  
Rous Sarcoma ◽  
Sarcoma Virus ◽  
Glucose Regulated Protein

To identify mRNAs with altered expression in Rous sarcoma virus (RSV)-transformed cells, we screened a chicken embryo fibroblast (CEF) cDNA library by differential hybridization. One clone, designated R1H, showed markedly elevated mRNA expression in RSV-transformed cells. Nucleotide sequence analysis indicated that R1H mRNA encodes 78-kilodalton glucose-regulated protein (GRP78). Chicken GRP78 was found to be very highly conserved in comparison with rat GRP78 (96% identity between chicken and rat amino acid sequences). In contrast to previous observations, we found that GRP78 was induced in RSV-transformed cells in the absence of glucose deprivation. When cells were grown in glucose-supplemented medium, the level of GRP78 mRNA was approximately fivefold higher in RSV-transformed CEF than in transformation-defective virus-infected or uninfected CEF. Similar changes in GRP78 protein content were also found. Using a temperature-sensitive mutant of RSV and supplemental glucose, we found a gradual increase in the level of GRP78 mRNA beginning at 4 h after shiftdown to permissive temperature. Uridine supplementation did not block the induction seen in CEF infected with a temperature-sensitive mutant. These results indicate that GRP78 is induced by p60v-src in the absence of glucose deprivation.

Identification of Phosphotyrosine-Containing Proteins in Untransformed and Rous Sarcoma Virus-Transformed Chicken Embryo Fibroblasts

1982 ◽  
Vol 2 (6) ◽  
pp. 653-665
Author(s):  
Ricardo Martinez ◽  
Kenji D. Nakamura ◽  
Michael J. Weber
Keyword(s):  
Protein Kinases ◽  
Rous Sarcoma Virus ◽  
Chicken Embryo ◽  
Cellular Protein ◽  
Transformed Cells ◽  
Phosphoamino Acid ◽  
Rous Sarcoma ◽  
Sarcoma Virus ◽  
Embryo Fibroblasts ◽  
Chicken Embryo Fibroblasts

Phosphorylation on tyrosine residues mediated by pp60 src appears to be a primary biochemical event leading to the establishment of the transformed phenotype in Rous sarcoma virus (RSV)-infected cells. To identify the cellular proteins that undergo tyrosine phosphorylation during transformation, a 32 P-labeled RSV-transformed chicken embryo cell extract was analyzed by electrophoresis on a polyacrylamide gel. After slicing the gel into approximately 60 slices, phosphoamino acid analyses were carried out on the protein recovered from each gel slice. Phosphotyrosine was found in every gel slice, with two major peaks of this phosphoamino acid around M r 's of 59 and 36 kilodaltons. When the same analysis was performed with cells infected with a transformation-defective src deletion mutant of RSV ( td NY101), significant and reproducible peaks of phosphotyrosine were found in only 2 of 60 gel slices. These gel slices corresponded to M r 's of 42 and 40 kilodaltons. Identical results were obtained with normal uninfected chicken embryo fibroblasts. We conclude from these observations that pp60 src or the combined action of pp60 src and pp60 src -activated cellular protein kinases cause the tyrosine-specific phosphorylation of a very large number of cellular polypeptides in RSV-transformed cells. In addition, untransformed cells appear to possess one or more active tyrosine-specific protein kinases which are responsible for the phosphorylation of a limited number of proteins. These proteins are different from the major phosphotyrosine-containing proteins of the transformed cells.

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