Biology Stack Exchange is a question and answer site for biology researchers, academics, and students. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

I was reading a paper,, where the authors claim that (e475)

Translation of the TfR (Transferrin Receptor) is regulated through sequences in the 3′ and 5′ UTRs (untranslated regions) of its mRNA. To study the regulation of TfR levels independently of translational control, we measured the levels of TfR-EGFP expressed from a plasmid lacking the regulatory sequences present in the endogenous TfR mRNA (Fig. 6A). Endogenous and GFP-tagged expressed TfR levels were reduced equally in response to Rabenosyn-5 depletion, ruling out an effect of this protein on transcriptional or translational control of TfR expression.

I believe I understand that the effect can not be post-translational, since TfR-GFP has no region for translational regulation and so it cannot be regulated by any translationally active regulating factor.

My question is: Wouldn't the statement above, that Rabenosyn-5 has no effect on protein transcription, require a proof that mRNA levels are not affected by this protein?

Fig. 6A,

share|improve this question
up vote 6 down vote accepted

From the Methods section:

Human TfR in plasmid cDNA was a gift from Tim McGraw (Weill-Cornell Medical College, New York, NY). Human TfR cDNA was subcloned in frame with EGFP in the Clontech pEGFP-N1 vector at the XhoI and BamHI restriction sites.

This TfR-GFP fusion protein does not have the endogenous TfR promoter. So it is not likely to be regulated by any TF that would directly regulate TfR transcription.

So they conclude that Rabenosyn-5 does not specifically regulate TfR expression.

share|improve this answer
I see. I guess if the cDNA plasmid would have had any regulatory sequence, they would have stated it. – TMOTTM Jul 19 '14 at 12:34
cDNA can have 5' and 3' UTRs but that is not the case here.. – WYSIWYG Jul 20 '14 at 6:04

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.