Problems with endogenous control - S18 (Feb/19/2008 )

Hello,

I have a problem with my TaqMan. I normaly use S18 as endogenous control (hGAPDH is somehow regulated in my samples). But the Ct values are not stable (not even in a triplicate). My gene of intrest always has almost the same Ct values in all samples treated the same way (as well as the triplicates), even with different series (different tissue). But my endogenous control is "jumping" around. As soon as I try to normalize my data, my statistics looks like the Himalaya.
I tried different reverse transcription protocols but nothing changed.

Any sugestions?

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Have you considered trying another HKG?

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Which ones? I just used the two mainly used ones in our lab.

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