Exam 15: Regulation of Gene Expression in Eukaryotes

If a mouse inherits a deletion in the SHH enhancer,what effect would you expect to see?

Galactose is absent,but you find active transcription of the GAL genes.Which protein is likely mutated or absent to allow for constitutive transcription of the GAL genes?

You have identified a mutation in a gene which 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?

During RNAi,what do miRNAs target for destruction?

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

What are the protein-binding sequences that direct enhancers to interact with the intended promoter and that block communication between enhancers and other promoter?

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

Which enzyme cuts dsRNA into 21-25 bp fragments during RNAi?

Explain what effect histone deacetylase inhibitors would have on gene expression and why they may be an effective anticancer therapeutic because of their impact on tumor suppressor genes.

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).

Gal4 binding leads to the formation of a multiprotein complex known as ________,which is an enhanceosome that forms after the activator protein binds.

Gal80 is mutated such that it cannot interact with Gal3.What effect would you expect to see in the presence of galactose?

What effect does methylation of CpG islands have on human promoters?

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 methylated,which of the following combinations of DNA fragments would you expect from this restriction digest?

Molecular biologists can determine experimentally whether a region of DNA contains closed chromatin or open chromatin by assessing the sensitivity of the region to

Both cis-acting sequences and trans-acting proteins affect gene expression in eukaryotic chromosomes.What are the three basic mechanisms by which trans-acting proteins access specific regulatory DNA sequences in eukaryotic chromosomes? Describe how chromatin is altered in each of these processes.

For the following gene,which mutant likely has lost its enhancer?

What are the two mechanisms by which chromatin remodelers can move nucleosomes?

________ in Drosophila results from the movement of the transcriptionally active w⁺ allele into the centromeric region of the fruit-fly X chromosome.

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