Suppose, you are doing an experiment with cancer cells and normal cells. You notice that "protein y" is much higher in cancer cells. Which of the following can help you determine whether the difference is due to a change in transcription or translation?
a) Analysis of proteins with similar amino acids to try to identify alternative splicing.
b) Adding an antibiotic that is known to prevent eukaryotic translation.
c) Remove the promoter for gene y.
d) Analysis of the mRNA levels for "y" in cancer vs. normal cells.
e) Remove the enhancer for gene y.
The right answer is d) Analysis of the mRNA levels for "y" in cancer vs. normal cells. In this question we should take decision: how to chose a variant that will point on exact reason of increasement the protein "y" level in tumor cells. Removing of the promotor of the "y" gene will stop transcription and abort protein expression - we will not understand if there was an impairment in protein translation. Similar reason is in the variant with removing the enhancer: it will not give us information about translation process. Case with alternative splicing can not be realised there because proteins in tumor cells can be unchanged in comparison to normal cells. Variant with antibiotic will not give us information about transcription status and only counting mRNA level will answer our question: in case of higher level of it we will find the case in higher rate of transcription. And if mRNA count will be the same, but protein "y" level will be higher, we can think about slower degradation of mRNA or impairments in translation process.