Question

In an experiment comparing two cell types, you notice that YFP (your favorite protein) encoded by YFG is abundant in cell type A but undetectable in cell type B. When you checked the mRNA transcript level, you find that they are equal in both cell types. Which of the options below provides the best explanation for this difference?

a. activating transcription factors contain a loss-of-function mutation in cell type B

b. the chromatin in cell type B is in the closed conformation

c. repressive transcription factors contain a gain-of-function mutation in cell type A

d. a ubiquitinating enzyme is expressed in cell type B but not in cell type A

Answer 1

the option A is incorrect because the transcript is already made in both the cell types.

The option B is incorrect because the chromatin is already exposed for transcription.

The Option is C incorrect because the transcription is already completed.

The option D provides best explanation for the said difference because Ubiquitination affects proteins in many ways: it can mark them for degradation via the proteasome, alter their cellular location, affect their activity, and promote or prevent protein interaction.