Hello everyone,
when I studied certain protein in patients who had different stage of liver disease (HCV, liver cirrhosis, HCC) and control group, I surprised that ELISA showed difference in the levels of this protein in serum but no difference have been showed in gene expression by real time _PCR and fold change equal 1 or 0.99 in all groups
so, I want to ask is there any reason that make gene expreesion the same in different groups but protein levels difference?
In general many people misinterpret rtPCR data this way. Protein levels can be way different for example due to protein stability and or translational control.
Michael is right, RT data (from biopsy material?) not always reflect the changes in protein levels, especially if you are working with serum of patients. It depends on the production rate/secretion rate of your protein of interest (is it actively secreted or a sign of cell damage like the transaminases?), the stability in serum and the excretion/degradation.
Thanks for all of you for your valuable comments this protein is kallistatin it is antifibrotic ,antiangiogenic protein it is normally secreted by liver so it decreases in liver cirhhosis, but elevates in HCC to fight cancer.
In protein detection by ELISA, it showed significant difference between groups, but when mRNA expression was measured by real time PCR, there is no difference between groups (ralative conc 0.99,0.98, 1.01 ,etc)......is there any explanation for that?
second; when I try to apply the equation of
ΔCT = CT (target gene) – CT (endogenous reference gene) ΔΔCT = average ΔCT (sample of interest) – average ΔCT (reference sample) FC= 2^(- ΔΔCT) the result of software is completely different with that appered by equation, also there are 2 curve by software and I don't know what does it mean ?
Here is an example of the result waiting for your kind response
Thanks alot best wishes
Is there any reason that make protein show difference between groups but no difference have been showed by real time PCR?. Available from: https://www.researchgate.net/post/Is_there_any_reason_that_make_protein_show_difference_between_groups_but_no_difference_have_been_showed_by_real_time_PCR [accessed Apr 7, 2017].
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