Exam 15: Regulation of Gene Expression in Eukaryotes

For the following gene, you notice the following results. Mutant # Deletion Region % Transcription (lungs)% Transcription (kidneys) WT None 100% 100% 1 1-200 150% 150% 2 250-400 100% 100% 3 500-800 50% 50% 4 950-1100 0% 100% What type of sequence has been mutated in mutant 4?

Which protein binds to the silencer sequence and promotes transcriptional silencing in the presence of glucose?

The gene encoding coat color is X-linked, and male cats have a single copy of the X chromosome. They can therefore express either the O or o allele, resulting in orange or black coat, respectively. Female cats, on the other hand, have two copies of the X chromosome. Thus, they can be heterozygous and express either orange or black. Using this information, list the possible genotypes for these individuals: • orange male • orange female • black male • black female • tortoiseshell

Typically, acetylation of histone tails leads to __________.

A region of chromatin has recently become DNAse I hypersensitive. Which enzyme has been activated to cause this change in chromatin structure?

Which protein complex directs DNA bending into loops that contact RNA polymerase and transcription factors bound at the core promoter or with protein complexes bound to proximal promoter elements?

Which molecules bind regulatory sequences of DNA to encourage positive regulation of transcription?

What are the common types of epigenetic modifications? Describe how epigenetic modifications can assist in predicting whether a gene is active or inactive in a cell.

In the GAL gene system, which protein binds to the activation domain of the activator protein, ultimately blocking transcription in the absence of galactose?

In vertebrates and plants, what types of modifications to the N-terminal tails of histones lead to heterochromatin formation?

What are three proteins or groups of proteins you would expect to find bound to the core promoter region in eukaryotes?

In yeast in the presence of galactose, you unexpectedly find that transcription is still blocked. Assuming Gal80 is present and functional, which other protein may be mutated to prevent transcriptional activation?

Which protein complex binds dsRNA fragments to generate ssRNAs for RNAi?

What gene is critical for establishment of X-inactivation in mammals?

In yeast, which gene would you expect to be activated during phosphate starvation?

How does transcription inhibition differ between prokaryotes and eukaryotes? Describe the two mechanisms used by eukaryotes to direct the enhancers toward certain promoters and away from others.

The imprinting control region (ICR)involved in genomic imprinting on chromosome 15 is what type of sequence?

Eukaryotes use these highly specialized enhancer elements, which regulate the transcription of multiple genes packaged in complexes of closely related genes (e.g., β-globin).

You have identified a mutation in a gene that also seems to decrease transcription of another gene 2000 bp away from the mutation site. What regulatory sequence, which may be found within another gene, has likely been mutated in this instance?

For the following gene, MspI and HpaII restriction sites and their positions are indicated here. Recall that HpaII is methylation sensitive, while MspI is not. If this gene is being actively transcribed, how many fragments would you expect from this restriction digest?