THE BEHAVIOUR OF TWO STRAINS OF MURINE SARCOMA VIRUS IN VITRO

1970 ◽  
Vol 48 (1) ◽  
pp. 105-114 ◽  
Author(s):  
PJ Simons
Keyword(s):  
Murine Sarcoma Virus ◽  
Sarcoma Virus ◽  
Murine Sarcoma

Mouse cells contain two distinct ras gene mRNA species that can be translated into a p21 onc protein

1982 ◽  
Vol 2 (11) ◽  
pp. 1339-1345
Author(s):  
R W Ellis ◽  
D DeFeo ◽  
M E Furth ◽  
E M Scolnick
Keyword(s):  
Normal Mouse ◽  
Velocity Sedimentation ◽  
Ras Gene ◽  
Mrna Species ◽  
P21 Ras ◽  
Murine Sarcoma Virus ◽  
Sarcoma Virus ◽  
Mouse Cells ◽  
Murine Sarcoma

The Kirsten (Ki) and Harvey (Ha) strains of murine sarcoma virus encode a 21,000-dalton protein (p21 ras) which is the product of the transforming gene of these viruses. Normal cells express low levels of p21 ras encoded by cellular genes (Ki-ras and Ha-ras) homologous to the Ki and Ha murine sarcoma virus transformation genes. A bone marrow-derived mouse cell line, 416B, has been shown to express unusually high levels of p21 ras. In this manuscript, we investigated the molecular biology of p21 ras gene expression in 416B and other normal mouse cells. We identified four distinct polyadenylated and polysome-associated RNAs, two related to Ki-ras and two to Ha-ras. The levels in 416B cells of the two Ki-ras RNAs, sized 5.2 and 2.0 kilobases, were both elevated approximately 25-fold over levels found in normal mouse cells; there was no corresponding change in 416B cells in the levels of the two Ha-ras RNAs. We partially purified the two Ki-ras mRNAs and separated them by velocity sedimentation in sucrose density gradients. Both the 5.2- and 2.0-kilobase mRNAs could be translated in vitro into p21 ras. These results show that a cellular onc protein can be translated from two distinct cellular mRNA species.

scholarly journals A SCANNING ELECTRON MICROSCOPE STUDY OF SURFACE FEATURES OF VIRAL AND SPONTANEOUS TRANSFORMANTS OF MOUSE BALB/3T3 CELLS

1973 ◽  
Vol 59 (3) ◽  
pp. 633-642 ◽  
Author(s):  
Keith R. Porter ◽  
George J. Todaro ◽  
Virginia Fonte
Keyword(s):  
Parent Cell ◽  
Cell Of Origin ◽  
3T3 Cells ◽  
Scanning Electron Microscope Study ◽  
Murine Sarcoma Virus ◽  
Sarcoma Virus ◽  
Surface Morphologies ◽  
Murine Sarcoma ◽  
Scanning Electron

Cells of the mouse line Balb/3T3 as well as three virus-induced transformants and two spontaneous transformants grown in vitro have been studied for their topography by scanning electron microscopy. The parent cell in confluent culture closely resembles an endothelial cell in its form and in the structure of its association with adjacent cells. The tumorigenic transformants produced by SV40, murine sarcoma virus, or polyoma viruses are fusiform to pleomorphic and distinctly different from the cell of origin. They show relatively smooth surfaces except for blebs and marginal microvilli. Perhaps most surprising is the similarity they bear to one another. This is made the more singular by the very different form shown by the tumorigenic transformants of spontaneous origin. One of these, S2-4, possesses a thickened rather than the lamellar form of the parent A31 cell and is covered by long microvilli and many spherical blebs. The other, TuT3, more closely resembles the cell of origin but shows extensive ruffling at its margins. All transformants grow without evidence of contact inhibition. The significance of the surface morphologies and the factors influencing cell form are discussed.

In Vivo and In Vitro Studies on the Morphogenesis of Tumors Induced by Murine Sarcoma Virus (Harvey) 2

1973 ◽  
Vol 51 (5) ◽  
pp. 1541-1549 ◽  
Author(s):  
W. R. Thomas ◽  
E. J. Aw ◽  
J. M. Papadimitriou ◽  
P. J. Simons
Keyword(s):  
In Vitro Studies ◽  
Murine Sarcoma Virus ◽  
Sarcoma Virus ◽  
Murine Sarcoma

scholarly journals Decreased susceptibility to calpains of v-FosFBR but not of v-FosFBJ or v-JunASV17 retroviral proteins compared with their cellular counterparts

1997 ◽  
Vol 323 (3) ◽  
pp. 685-692 ◽  
Author(s):  
Ann-Muriel STEFF ◽  
Serge CARILLO ◽  
Magali PARIAT ◽  
Marc PIECHACZYK
Keyword(s):  
Cysteine Proteases ◽  
Calcium Dependent ◽  
Peptide Motifs ◽  
Interesting Possibility ◽  
Murine Sarcoma Virus ◽  
Sarcoma Virus ◽  
Infected Cells ◽  
Murine Sarcoma

The c-Fos and c-Jun transcription factors are rapidly turned over in vivo. One of the multiple pathways responsible for their breakdown is probably initiated by calpains, which are cytoplasmic calcium-dependent cysteine proteases. The c-fos gene has been transduced by two murine oncogenic retroviruses called Finkel-Biskis-Jenkins murine sarcoma virus (FBJ-MSV) and Finkel-Biskis-Reilly murine sarcoma virus (FBR-MSV); c-jun has been transduced by the chicken avian sarcoma virus 17 (ASV17) retrovirus. Using an in vitro degradation assay, we show that the mutated v-FosFBR, but not v-FosFBJ or v-JunASV17, is resistant to calpains. This property raises the interesting possibility that decreased sensitivity to calpains might contribute to the tumorigenic potential of FBR-MSV by allowing greater accumulation of the protein that it encodes in infected cells. It has also been demonstrated that resistance to cleavage by calpains does not result from mutations that have accumulated in the Fos moiety of the viral protein but rather from the addition of atypical peptide motifs at its both ends. This observation raises the interesting possibility that homologous regions in viral and cellular Fos either display slightly different conformations or are differentially accessible to interacting proteins.

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