Properties of 3T3 Cells Transformed by Murine Sarcoma Virus in the Absence of Replicating Murine Leukemia Helper Virus

Author(s):  
R. H. Bassin ◽  
L. A. Phillips ◽  
M. J. Kramer ◽  
D. K. Haapala ◽  
P. T. Peebles ◽  
...  
1986 ◽  
Vol 6 (5) ◽  
pp. 1706-1710 ◽  
Author(s):  
M Ruta ◽  
R Wolford ◽  
R Dhar ◽  
D Defeo-Jones ◽  
R W Ellis ◽  
...  

We present the nucleotide sequence of the coding region of the rat c-rasH-1 gene and a partial sequence analysis of the rat c-rasH-2 gene. By comparing these sequences with the Harvey murine sarcoma virus ras gene, we predict that the p21 protein encoded by the Harvey virus differs from the cellular c-rasH-1-encoded p21 at only two amino acids; those at positions 12 and 59. Alterations at each of these positions may play a role in activating the viral p21 protein. The c-rasH-2 gene is likely to be a nonfunctional pseudogene because it lacks introns, cannot be activated to transform NIH 3T3 cells, and differs in sequence from both c-rasH-1 and v-rasH at several base pair positions.


1973 ◽  
Vol 59 (3) ◽  
pp. 633-642 ◽  
Author(s):  
Keith R. Porter ◽  
George J. Todaro ◽  
Virginia Fonte

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.


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