mRNA level and protein level correlation?

Dr. Hiranya S. Roychowdhury hroychow at
Thu Mar 18 11:41:57 EST 2004

More often than not, one can hardly correlate transcript levels with proteins 
produced simply because transcription in eukaryotes is not linked either 
physically (spatially) or temporally to translation.  Protein levels may also 
be controlled post-transcriptionally according to the system's needs and also 
according to the "feed-stock" available.  These factors need to be addressed 
through independent experiments. 

Quoting Peter Frank <peter_frankde at>:

> In order to compare two systems (treated vs untreated) I quantitated
> the mRNA level of my target gene using real-time PCR and quantitated
> the protein level using quantitative Western blotting.
> According to the real-time RT-PCR results the mRNA level is around
> 3-fold higher in the treated system compared to the untreated system.
> According to the quantitative Western blotting results the protein
> level is only around 1.6-fold higher in the treated system compared to
> the untreated system.
> I would rather have expected to get the same or even higher fold
> change in protein level. The incubation time after the treatment was
> 24 h. The target protein is a transcription factor and I would expect
> such a protein to be synthesized relatively quickly.
> Does anyone have any idea why there is such a discrepancy between the
> changes in mRNA level and protein level (i.e. considerably lower
> changes in protein level than in mRNA level)?
> Peter

Hiranya S. Roychowdhury, Ph.D.
Coll. Asst. Professor,
Molecular Biology,
Dept. of Chemistry & Biochemistry
Rm# 336, Chemistry Bldg.; MSC 3MLS
New Mexico State University
Las Cruces, NM 88003

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