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different Ct ... - (Apr/06/2007 )

I'm Samuela, is the first time that I write in this forum..
I used the same control in each Real-Time experiments to compare the results...but in the first experiment the Ct - control value was 19.16 while in the second plate was 22.98...Why??the all plate in the second experiment was lower then the first...
Another question: cell in culture (in different days) may change the mRNA expression?



Hi Samu, welcome to the Forum!

You just found the reason, why you should allways run samples and controls on the same plate - there are allways slight differences, due to pipetting, speed of preparing the samples, temperature in the lab, solar radiation wink.gif, the way you slept in the night before the experiments. Having controls and samples on the same plate reduces the probability of larger variation. So, your results look absolutely normal to me...
Cell culture - depends a lot on the cells and what they are doing ... if you are looking for example at embryocarcinoma cells a part of your cells will start to differentiate, what surely changes the mRNA expression. So, try to be sure to make experiments at a comparable time point after the transfer.