Marnie Blewitt Author Answered Sep 14, 2014
Molecular Medicine Division, The Walter and Eliza Hall Institute of Medical Research, Australia
Dear Steven,
The p53 knockdown is essential prior to oncogenic Ras transduction, as otherwise Ras with cause senescence.
With regards to why your knockout cells don't create a neoplasm, there are a number of possibilities. Were the knockout cells passaged, transduced and selected alongside the controls? In this way, can you be sure they were properly transformed? If so, it is possible that the knockout cells cannot grow in vivo. Potentially this could be because the gene that has been knocked out is downstream of Ras, meaning even with Ras overexpression you don't transform the cells.