Deck 12: Transcription Activators in Eukaryotes

Question 1

DNA is complexed with protein in a structure called ___________.

Answer 1

chromatin

Question 2

An experiment is planned to look at the effect of blocking the thyroid hormone receptor.Which of the following is a good technique to employ?

A)phosphorylation
B)methylation
C)ubiquitination
D)sumoylation
E)all of the choices are correct.

Answer 2

D

Question 3

Which of the following approaches would you use to loosen the interaction of the histones with DNA in an extract that you have prepared?

A)methylate the DNA
B)methylate the histone
C)acetylate the histones
D)phosphorylate the histones
E)phosphorylate the DNA

Answer 3

C

Question 4

Which of the following is a target site for GAL4?

A)UAS_G
B)CCAAT
C)GCAAT
D)UAS_G and CCAAT
E)CCAAT and GCAAT

Question 5

Select the feature that is not true of the GAL4 protein.

A)contains six cysteines
B)contains zinc fingers
C)contains zinc ions in the DNA binding motif
D)contains a-helix
E)is a member of zinc-containing family

Question 6

One way to prevent the activation of certain cells by a growth factor is to

A)block phosphorylation of the cytoplasmic domain of the receptor.
B)block dimerization of the receptor.
C)block phosphorylation on the extracellular domain.
D)block phosphorylation of the cytoplasmic domain of the receptor and block dimerization of the receptor.
E)block phosphorylation of the cytoplasmic domain of the receptor and block phosphorylation on the extracellular domain.

Question 7

Predict the effect of the addition of excess acetyltansferase to in vitro transcription assay.

A)It will likely loosen the interaction of histone with DNA.
B)It will lead to a tighter association of histone with DNA,resulting in reduced transcription.
C)It will have no effect on the interaction of DNA with histones.
D)There will be a complete repression of transcription.
E)None of the choices are correct.

Question 8

The glucocorticoid receptor is activated by binding to

A)its hormone ligand then moving to the nucleus.
B)its hormone ligand protein partner and then moving to the nucleus.
C)its hormone partner in the nucleus.
D)DNA and then to its hormone ligand.
E)None of the choices are correct.

Question 9

Which of the following is a reasonable way to explain the ability of enhancers to act at a distance?

A)The activator binds to an enhancer,changing the supercoiling state of the DNA and opening up the promoter to general transcription factors.
B)The activator binds to an enhancer,slides along the DNA until it encounters the promoter,and activates transcription.
C)An activator binds to an enhancer,creating loops in the DNA,which leads to the interaction of proteins at the promoter and activation of transcription.
D)An activator binds to an enhancer and a downstream segment to form a loop,which causes the protein to track toward the promoter and activate transcription.
E)All of the choices explanations are possible.

Question 10

Which of the following are typical features of transcriptional activators?

A)transcription-activation domain
B)DNA-binding domain
C)kinase domain
D)transcription-activation domain and DNA-binding domain
E)transcription-activation domain and kinase domain

Question 11

Which of the following are found in bZip and HLH domains?

A)leucine zipper
B)helix-loop-helix regions
C)zinc fingers
D)leucine zipper and helix-loop-helix regions
E)helix-loop-helix regions and zinc fingers

Question 12

Which of the following effects is possible if LEF1 were omitted from an in vitro transcription assay that you were conducting to look at the expression of the TCR $\alpha$ gene?

A)no transcription
B)low levels of transcription
C)lack of bending in the promoter DNA
D)rapid initiation of transcription
E)no transcription,low levels of transcription,and lack of bending in the promoter DNA are all possible outcomes.

Question 13

In the Ras-Raf signaling pathway,MEK phosphorylates the protein kinase ERK to activate it.What does activated ERK do?

A)phosphorylate a variety of cytoplasmic proteins
B)move into the nucleus
C)phosphorylate and activate several activators in the nucleus
D)phosphorylate and activate Elk-1 in the nucleus
E)all of the above

Question 14

An enhanceosome is a nucleoprotein complex containing a collection of activators.

Question 15

Which of the following can be found in DNA-binding domains?

A)zinc fingers
B)glutamine-rich regions
C)bZIP motifs
D)bHLH motif
E)all of the choices are correct.

Question 16

One effect of mutation or deleting the activation domain of a transcriptional activator would be

A)reduction in the binding of TFIIA.
B)reduction in the binding TFIID.
C)binding of the activator to DNA,without activating transcription.
D)reduction in the binding of TFIIA and reduction in the binding TFIID.
E)reduction in the binding TFIID and binding of the activator to DNA,without activating transcription.

Question 17

What is the most likely outcome of ubiquitination of a transcription activator such as CREB?

A)It will be stimulated to bind to corepressors.
B)It will become a target for proteasomes.
C)It will be a target for chaperones.
D)It will have no effect on the activity of this protein.
E)None of the correct are correct.

Question 18

All of the following are true regarding homeodomains except

A)they contain about 60 amino acids.
B)they resemble prokaryotic helix-turn-helix domains.
C)they are a class of DNA-binding proteins.
D)they may be involved in the regulation of development.
E)they are repressors.

Question 19

Insulators are DNA elements that

A)shield genes from activation by blocking enhancer activity.
B)block gene activity by binding the operator regions.
C)block the coding region of genes,preventing transcription.
D)shield genes from activation by blocking enhancer activity and block gene activity by binding the operator regions.
E)block gene activity by binding the operator regions and block the coding region of genes,preventing transcription.

Question 20

Predict the effect of blocking GTPase activity by a mutant lacking the GAP gene.Which of the following would be a possible outcome if cells in this mutant are treated with a growth factor?

A)a sustained level of transduction
B)dramatically reduced interaction of the growth factor with the receptor
C)inactivation of MEK
D)dephosphorylation of the growth factor receptor
E)inactivation of Elk

Question 21

Heterodimers are sometimes found in the dimerization domain of transcription activators.

Question 22

Many genes have more than one activator-binding site,so that they respond to multiple stimuli and establish fine control of gene expression.

Question 23

Nuclear receptors interact with steroids and other hormones form complexes that bind to hormone response elements in the cytoplasm.

Question 24

Some insulators have both insulator and barrier activity.

Question 25

An example of DNA-binding protein that contains a zinc finger motif is Gal4.

Question 26

Transcription activators help to boost transcription by recruiting RNA polymerase to promoters.

Question 27

Type II receptors reside in the cytoplasm where they bind to hormone ligands.

Question 28

Experimental evidence has shown that it is necessary for the promoter and the enhancer to be on the same chromosome in order to function together.

Question 29

The DNA-binding and activation domains of activator proteins are independent molecules.

Question 30

Nuclear receptors interact with endocrine-signaling molecules.

Question 31

Glucocorticoid response elements are enhancers that bind to a receptor-glucocorticod complex.