scholarly journals Stat3 Activation Is Required for Cellular Transformation by v-src

1998 ◽  
Vol 18 (5) ◽  
pp. 2553-2558 ◽  
Author(s):  
Jacqueline F. Bromberg ◽  
Curt M. Horvath ◽  
Daniel Besser ◽  
Wyndham W. Lathem ◽  
James E. Darnell
Keyword(s):  
Cell Lines ◽  
Cellular Transformation ◽  
Human Tumors ◽  
Dominant Negative ◽  
Wild Type ◽  
Mutant Proteins ◽  
Transformed Cell ◽  
Transformed Cell Lines ◽  
Relationship Of ◽  
The Relationship

ABSTRACT Stat3 activation has been associated with cytokine-induced proliferation, anti-apoptosis, and transformation. Constitutively activated Stat3 has been found in many human tumors as well as v-abl- and v-src-transformed cell lines. Because of these correlations, we examined directly the relationship of activated Stat3 to cellular transformation and found that wild-type Stat3 enhances the transforming potential of v-src while three dominant negative Stat3 mutants inhibit v-srctransformation. Stat3 wild-type or mutant proteins did not affect v-ras transformation. We conclude that Stat3 has a necessary role in v-src transformation.

scholarly journals Inhibition of p53 Transactivation Function by the Human T-Cell Lymphotropic Virus Type 1 Tax Protein

1998 ◽  
Vol 72 (2) ◽  
pp. 1165-1170 ◽  
Author(s):  
Cynthia A. Pise-Masison ◽  
Kyeong-Sook Choi ◽  
Michael Radonovich ◽  
Jürgen Dittmer ◽  
Seong-Jin Kim ◽  
...  
Keyword(s):  
T Cell ◽  
Cell Lines ◽  
Virus Type ◽  
Primary Role ◽  
Wild Type ◽  
Transformed Cell ◽  
Human T Cell ◽  
Wild Type P53 ◽  
Transformed Cell Lines

ABSTRACT Human T-cell lymphotropic virus type 1 (HTLV-1) is the etiologic agent for adult T-cell leukemia. HTLV-1 transforms lymphocytes, and there is increasing evidence that the virus-encoded protein, Tax, plays a primary role in viral transformation. We have shown that wild-type p53 in HTLV-1-transformed cells is stabilized. This study was initiated to directly analyze whether the p53 in HTLV-1-transformed cell lines was transcriptionally active and to identify the viral gene product responsible for stabilization and inactivation. Transfection experiments using a p53-responsive reporter plasmid and γ-irradiation studies demonstrate that the wild-type p53 in HTLV-1-transformed cell lines is not fully active. Further, we demonstrate that the HTLV-1-transforming protein, Tax, stabilizes and inactivates p53 function. Cotransfection of Tax with p53 results in a greater than 10-fold reduction in p53 transcription activity. Using Gal4-p53 fusion proteins, we demonstrate that Tax inhibition of p53 transactivation function is independent of sequence-specific DNA binding. Moreover, Tax inhibits p53 function by interfering with the activity of the N-terminal activation domain (amino acids 1 to 52). We conclude that Tax is involved in the inactivation of p53 function and stabilization of p53 in HTLV-1-infected cells. The functional interference of p53 function by Tax may be important for transformation and leukemogenesis.

scholarly journals Effect of tunicamycin on cell growth and morphology of nontransformed and transformed cell lines.

1979 ◽  
Vol 43 (7) ◽  
pp. 1553-1561 ◽  
Author(s):  
Kenji KOHNO ◽  
Akiyoshi HIRAGUN ◽  
Hiromi MITSUI ◽  
Akira TAKATSUKI ◽  
Gakuzo TAMURA
Keyword(s):  
Cell Growth ◽  
Cell Lines ◽  
Transformed Cell ◽  
Transformed Cell Lines

scholarly journals G3BP1 promotes stress-induced RNA granule interactions to preserve polyadenylated mRNA

2015 ◽  
Vol 209 (1) ◽  
pp. 73-84 ◽  
Author(s):  
Anaïs Aulas ◽  
Guillaume Caron ◽  
Christos G. Gkogkas ◽  
Nguyen-Vi Mohamed ◽  
Laurie Destroismaisons ◽  
...  
Keyword(s):  
Normal Stress ◽  
Cell Lines ◽  
Translational Repression ◽  
Primary Neurons ◽  
Processing Bodies ◽  
Transformed Cell ◽  
Upstream Regulator ◽  
Functional Consequences ◽  
Transformed Cell Lines ◽  
Polyadenylated Mrna

G3BP1, a target of TDP-43, is required for normal stress granule (SG) assembly, but the functional consequences of failed SG assembly remain unknown. Here, using both transformed cell lines and primary neurons, we investigated the functional impact of this disruption in SG dynamics. While stress-induced translational repression and recruitment of key SG proteins was undisturbed, depletion of G3BP1 or its upstream regulator TDP-43 disturbed normal interactions between SGs and processing bodies (PBs). This was concomitant with decreased SG size, reduced SG–PB docking, and impaired preservation of polyadenylated mRNA. Reintroduction of G3BP1 alone was sufficient to rescue all of these phenotypes, indicating that G3BP1 is essential for normal SG–PB interactions and SG function.

scholarly journals Rad51 catalytic mutants differentially affect the Rad51 nucleoprotein filament in vivo

2016 ◽  
Author(s):  
Maureen M. Mundia ◽  
Alissa C. Magwood ◽  
Mark D. Baker
Keyword(s):  
Homologous Recombination ◽  
Dna Synthesis ◽  
Cell Lines ◽  
Atp Hydrolysis ◽  
Dominant Negative ◽  
Strand Exchange ◽  
Wild Type ◽  
Hybridoma Cell Lines ◽  
Insight Into

ABSTRACTIn this study, we utilized mouse hybridoma cell lines stably expressing ectopic wild-type Rad51, or the Rad51-K133A and Rad51-K133R catalytic mutants deficient in ATP binding and ATP hydrolysis, respectively, to investigate effects on the Rad51 nucleoprotein filament in vivo. Immunoprecipitation studies reveal interactions between ectopic wild-type Rad51, Rad51-K133A and Rad51-K133R and endogenous Rad51, Brca2 and p53 proteins. Importantly, the expression of Rad51-K133A and Rad51-K133R catalytic mutants (but not wild-type Rad51) targets endogenous Rad51, Brca2 and p53 proteins for proteasome-mediated degradation. Expression of Rad51-K133R significantly reduces nascent DNA synthesis (3’ polymerization) during homologous recombination (HR), but the effects of Rad51-K133A on 3’ polymerization are considerably more severe. Provision of additional wild-type Rad51 in cell lines expressing Rad51-K133A or Rad51-K133R does not restore diminished levels of endogenous Brca2, Rad51 or p53, nor restore the deficiency in 3’ polymerization. Cells expressing Rad51-K133A are also significantly reduced in their capacity to drive strand exchange through regions of heterology. Our results reveal an interesting mechanistic dichotomy in the way mutant Rad51-K133A and Rad51-K133R proteins influence 3’ polymerization and provide novel insight into the mechanism of their dominant-negative phenotypes.

The preferential cytotoxicity of reovirus for certain transformed cell lines

1977 ◽  
Vol 54 (4) ◽  
pp. 307-315 ◽  
Author(s):  
G. Hashiro ◽  
P. C. Loh ◽  
Jenny T. Yau
Keyword(s):  
Cell Lines ◽  
Transformed Cell ◽  
Transformed Cell Lines
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