Correlated effects of external magnesium on cation content and DNA synthesis in cultured chicken embryo fibroblasts

1977 ◽  
Vol 92 (1) ◽  
pp. 23-31 ◽  
Author(s):  
Hisashi Sanui ◽  
Harry Rubin
Keyword(s):  
Dna Synthesis ◽  
Chicken Embryo ◽  
Cation Content ◽  
Embryo Fibroblasts ◽  
Chicken Embryo Fibroblasts

Kinetics of unscheduled DNA synthesis in UV-irradiated chicken embryo fibroblasts

1985 ◽  
Vol 146 (3) ◽  
pp. 305-310 ◽  
Author(s):  
L. Roza ◽  
M.H. Wade ◽  
G.P. van der Schans ◽  
P.H.M. Lohman ◽  
F. Berends
Keyword(s):  
Dna Synthesis ◽  
Chicken Embryo ◽  
Unscheduled Dna Synthesis ◽  
Embryo Fibroblasts ◽  
Kinetics Of ◽  
Chicken Embryo Fibroblasts

scholarly journals Increased ouabain-sensitive 86Rubidium uptake after mitogenic stimulation of quiescent chicken embryo fibroblasts with purified multiplication-stimulating activity.

1977 ◽  
Vol 73 (3) ◽  
pp. 761-767 ◽  
Author(s):  
G L Smith
Keyword(s):  
Dna Synthesis ◽  
Chicken Embryo ◽  
Enzyme Assay ◽  
Specific Inhibitor ◽  
Early Event ◽  
Free Medium ◽  
Quiescent Cells ◽  
Embryo Fibroblasts ◽  
Chicken Embryo Fibroblasts ◽  
Stimulation Of

Multiplication-stimulating activity (MSA), a protein which stimulates DNA synthesis and growth of chicken embryo fibroblasts, was purified from serum-free medium conditioned by the growth of a rat liver cell line. Purified MSA was shown to rapidly stimulate ouabain-sensitive Na+, K+-ATPase activity as measured by both enzyme assay and rate of 86Rubidium uptake. Labeled ouabain binding was also shown to increase after stimulation of quiescent cells by serum or purified MSA. Conditions which interfere with the ability of the cells to accumulate potassium, such as the presence of the specific inhibitor, ouabain; incubation in potassium-free medium; or the presence of the potassium ionophore, valinomycin, were all demonstrated to inhibit the stimulation of DNA synthesis by serum or purified MSA. These results suggest that an early event in the stimulation of DNA synthesis by purified MSA is an activation of membrane Na+, K+-ATPase with a resulting accumulation of potassium ions inside the cell.

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.

Differential regulation of glucose transporter isoforms by the src oncogene in chicken embryo fibroblasts

1991 ◽  
Vol 11 (9) ◽  
pp. 4448-4454
Author(s):  
M K White ◽  
T B Rall ◽  
M J Weber
Keyword(s):  
Glucose Transport ◽  
Chicken Embryo ◽  
Glucose Transporter ◽  
Sequence Similarity ◽  
Transporter Protein ◽  
Mrna Induction ◽  
Embryo Fibroblasts ◽  
Type 3 ◽  
Chicken Embryo Fibroblasts

The increase in glucose transport that occurs when chicken embryo fibroblasts (CEFs) are transformed by src is associated with an increase in the amount of type 1 glucose transporter protein, and we have previously shown that this effect is due to a decrease in the degradation rate of this protein. The rate of CEF type 1 glucose transporter biosynthesis and the level of its mRNA are unaffected by src transformation. To study the molecular basis of this phenomenon, we have been isolating chicken glucose transporter cDNAs by hybridization to a rat type 1 glucose transporter probe at low stringency. Surprisingly, these clones corresponded to a message encoding a protein which has most sequence similarity to the human type 3 glucose transporter and which we refer to as CEF-GT3. CEF-GT3 is clearly distinct from the CEF type 1 transporter that we have previously described. Northern (RNA) analysis of CEF RNA with CEF-GT3 cDNA revealed two messages of 1.7 and 3.3 kb which were both greatly induced by src transformation. When the CEF-GT3 cDNA was expressed in rat fibroblasts, a three-to fourfold enhancement of 2-deoxyglucose uptake was observed, indicating that CEF-GT3 is a functional glucose transporter. Northern analyses using a CEF-GT3 and a rat type 1 probe demonstrated that there is no hybridization between different isoforms but that there is cross-species hybridization between the rat type 1 probe and the chicken homolog. Southern blot analyses confirmed that the chicken genomic type 1 and type 3 transporters are encoded by distinct genes. We conclude that CEFs express two types of transporter, type 1 (which we have previously reported to be regulated posttranslationally by src) and a novel type 3 isoform which, unlike type 1, shows mRNA induction upon src transformation. We conclude that src regulates glucose transport in CEFs simultaneously by two different mechanisms.

The chicken ubiquitin gene contains a heat shock promoter and expresses an unstable mRNA in heat-shocked cells

1986 ◽  
Vol 6 (12) ◽  
pp. 4602-4610
Author(s):  
U Bond ◽  
M J Schlesinger
Keyword(s):  
Heat Shock ◽  
Chicken Embryo ◽  
Actinomycin D ◽  
Genomic Library ◽  
Protein Coding ◽  
Noncoding Regions ◽  
Genomic Location ◽  
Embryo Fibroblasts ◽  
The Stability ◽  
Chicken Embryo Fibroblasts

A chicken genomic library was screened to obtain genomic clones for ubiquitin genes. Two genes that differ in their genomic location and organization were identified. One gene, designated Ub I, contains four copies of the protein-coding sequence arranged in tandem, while the second gene, Ub II, contains three. The origin of the two major mRNAs that are induced after heat shock in chicken embryo fibroblasts was determined by generating DNA probes from the 5'-and 3'-noncoding regions of the two genes. Both mRNAs are transcribed from Ub I, the larger being the unspliced precursor of the smaller. A 674-base-pair intron was located within the 5'-noncoding region of Ub I. The second gene, Ub II, does not appear to code for an RNA species in normal or heat-shocked chicken embryo fibroblasts. The expression of ubiquitin mRNA during heat shock and recovery was examined. Addition of actinomycin D before heat shock completely abolished the response of ubiquitin mRNA to the stress. Analysis of the stability of the mRNA during recovery revealed that the mRNA accumulated during the heat shock is rapidly degraded with a half-life of approximately 1.5 h, suggesting a specialized but transient role for ubiquitin during heat shock.

Plasminogen activator: analysis of enzyme induction by ultraviolet irradiation mapping

1981 ◽  
Vol 1 (10) ◽  
pp. 884-890
Author(s):  
R Miskin ◽  
E Reich ◽  
K Dixon
Keyword(s):  
Plasminogen Activator ◽  
Cross Sections ◽  
Ultraviolet Irradiation ◽  
Chicken Embryo ◽  
Phorbol Esters ◽  
Transformed Cells ◽  
Normal Cells ◽  
Embryo Fibroblasts ◽  
Mapping Techniques ◽  
Chicken Embryo Fibroblasts

Ultraviolet irradiation mapping techniques have previously been used to study the organization of eucaryotic gene classes and transcription units. We used the same method to probe some regulatory phenomena observed in the induction of plasminogen activator (PA) biosynthesis: PA synthesis in chicken embryo fibroblasts is induced by tumor-promoting phorbol esters and by retinoic acid; furthermore, PA induction by phorbol esters is synergistic with transformation, being 10- to 20-fold greater in virus-transformed cells than in normal cells. We found that the ultraviolet irradiation inactivation cross sections for PA induction by phorbol esters and by retinoate differed significantly, suggesting that these agents induce PA biosynthesis by different mechanisms. On the other hand, the ultraviolet irradiation sensitivity of phorbol ester induction in normal chicken embryo fibroblasts was the same as in transformed cells, indicating that the synergism of transformation and phorbol esters is probably not due to different pathways of PA induction.

Sign in / Sign up

Export Citation Format

Share Document