Question

5. Both epigenetic and genetics can affect gene expression. Below are a few situations affecting Protein X. Please describe for each situation if: A) protein X will be more or less transcribed (or no change), AND B) if this is due to genetic or epigenetic changes.

A. Mutation in Protein D so it can no longer target Protein X for deacetylation

B. Mutation of the consensus sequence in the promoter of Protein X, resulting in increased association with RNA polymerase

C. Mutation in Protein X causing it to be constitutively active

D. Protein X acquires three methylation marks at H3K27 in the promoter region

Answer 1

A) no change because protein D is responsible for post translation modification and doesn't affect it's expression levels; it's is a genetic change as mutation in a gene always results in altered sequence.

B) more transcribed because increased association of RNA polymerase will cause increase transcription; genetic change because mutation in promoter sequence will result in an altered sequence.

C) increased transcription because it is constitutively active and cannot be inhibited; genetic because mutation alters gene sequence.

D) less transcription because more methylation at a DNA region would cause it to be more tightly packed and less available for transcription; epigenetic because there is no mutation occurring and hence the sequence is unaltered.