inconsistent result from real time PCR - (Apr/09/2007 )

I have done real time PCR for some of gene of interests by using Cybergreen. i have repeat the experiment four time each with three replicate. However, the result is not consistent. the gene up in two trial and down in other two trial. Any suggestion for this condition? thank you

Though I'm not a RT-PCR expert, I can say these things;

first, think about the conditions when you extracted your RNA.. there may be an unexpected factor to influence your RNA

second, did you get a standard curve of your genes? RT-PCR results are not linear when gene expression is too high or low, so you need to be sure of your Ct values in the linear range.

Another possibility - the gene doesn't really change it's expression in your experiments - your just measuring the normal variance...