Mammalian spermatogonial stem cells are a special type of adult stem cells 
because they can contribute to the next generation. Knockout studies have 
indicated a role for TRP53 and PTEN in insulating male germ cells from 
pluripotency, but the mechanism by which this is achieved is largely unknown. To 
get more insight in these processes, an RNAi experiment was performed on the 
mouse spermatogonial stem cell line GSDG1. Lipofectaminemediated transfection of 
siRNAs directed against Trp53 and Pten resulted in decreased expression levels 
as determined by quantitative RT-PCR and immunoblotting. The effects of 
knockdown were examined by determining the expression levels of genes that are 
involved in reprogramming and pluripotency of cells, specifically Nanog, Eras, 
c-Myc, Klf4, Oct4, and Sox2. Additionally, the effects of TRP53 or PTEN 
knockdown on Plzf and Ddx4 expression were measured, which are highly expressed 
in spermatogonial stem cells and differentiating male germ cells, respectively. 
The main finding of this study is that knockdown of Trp53 and Pten independently 
resulted in significantly higher expression levels of the 
pluripotency-associated gene Nanog, and we hypothesize that TRP53 and PTEN 
mediated repression is important for the insulation of male germ cells from 
pluripotency.