Deck 17: Regulation of Gene Expression in Eukaryotes

Question 1

UASs (upstream activating sequences) are DNase hypersensitive. This means that ________.

A) a UAS is constitutively open
B) more than one strand of DNA exists in each UAS
C) each UAS is likely to be single-stranded
D) each UAS has more histone-binding sites than non-UAS sites
E) any given UAS is composed of a double-stranded site with a bound repressor

Answer 1

A

Question 2

Which process seems to be the most similar between eukaryotic and prokaryotic genetic regulation?

A) transcriptional regulation
B) RNA splicing regulation
C) intron/exon shuffling
D) 5′-capping regulation
E) poly(A) tail addition

Answer 2

A

Question 3

In what way do upstream activator sequences (UASs), regulatory sequences in yeast, differ from enhancers and silencers?

A) UASs function only downstream.
B) UASs function only upstream.
C) Enhancers function only downstream.
D) UASs function in the middle of transcription units.
E) UASs can function only in the 5′-3′ direction.

Answer 3

B

Question 4

Describe three characteristics of enhancers and silencers.

Question 5

Describe the general structure of a transcription factor.

Question 6

Two modular elements that appear as consensus sequences upstream from RNA polymerase II transcription start sites are ________.

A) microsatellites and transposons
B) rDNA and nucleolar organizers
C) TATA and CAAT
D) TTAA and CCTT
E) enhancers and telomeres

Question 7

Describe how nucleosomes may influence gene transcription.

Question 8

Enhancers are said to be cis-acting. What is meant by cis-acting, and what are enhancers?

Question 9

Name three consensus sequences or modular DNA sequences that exist upstream from the coding regions of some eukaryotic genes.

Question 10

The two major components of the immune system are humoral and cellular immunity. The humoral component ________.

A) is involved in the production of antibodies
B) allows the T cells to produce antigens that then stimulate antibody production
C) plays a major role in the production of antigens
D) suppresses the production of T cells
E) is responsible for allowing horizontal gene transfer

Question 11

Describe the difference between a focused promoter and a dispersed promoter.

Question 12

In what way is 5′-azacytidine used (experimentally) in the treatment of sickle-cell anemia?

Question 13

List at least three levels or types of genetic regulation in eukaryotes.

Question 14

Because of the imprecision of molecular joining, recombination between LV and J regions shows considerable variation. Which additional circumstance contributes to this variation?

A) transmutation
B) hypermutation
C) transfection
D) conjugation
E) transduction

Question 15

In what way can 5′-azacytidine influence transcription?

Question 16

What is the general position of the consensus sequence called the GC box? What is its sequence?

A) promoter; CAAT
B) promoter; GGGCGG
C) terminator; CAAT
D) terminator; GGGCGG
E) attenuator; GGGCGG

Question 17

Transcription factors appear to be important molecules relating to the regulation of gene activity. Two general classes of transcription factors exist in eukaryotes. Briefly describe each.

Question 18

Channels between chromosomes in the interphase nucleus are called ________.

A) extrachromosomal elements
B) localized zones
C) nonlocalized zones
D) interchromosomal compartments
E) subchromosomal territories

Question 19

Which of the following clusters of terms applies when addressing enhancers or silencers as elements associated with eukaryotic genetic regulation?

A) cis-acting, variable orientation, variable position
B) trans-acting, fixed position, fixed orientation
C) cis-acting, fixed position, fixed orientation
D) cis-acting, variable position, fixed orientation
E) trans- and cis-acting, variable position

Question 20

What are the approximate positions of consensus sequences (modular elements) at the 5′ end of eukaryotic genes?

Question 21

In some cases, genes undergo amplification (local, multiple duplications) when additional gene products are in high demand. Would you consider gene amplification as a form of genetic regulation in eukaryotes? Explain your answer.

Question 22

Describe the function and general nature of promoters in eukaryotes.

Question 23

Mutations in the promoter region of the β-globin gene indicate that some areas are more sensitive than others. When mutations occur in consensus sequences (modular elements such as GC box, CAAT box, TATA box), does transcription usually increase or decrease?

Question 24

In what ways are eukaryotic transcription factors thought to function?

Question 25

Provide a general set of statements that describes an enhancer.

Question 26

List three general pathways in which eukaryotic mRNA is typically degraded in eukaryotes.

Question 27

In what way is gene rearrangement related to gene regulation? Give an example.

Question 28

What evidence indicates that steroid hormones exert their influence at the level of DNA?

Question 29

In general, one could say that fewer levels of regulation are possible in prokaryotes than in eukaryotes.

Question 30

List three major structural classifications of DNA-binding domains that are found in eukaryotic transcription factors.

Question 31

Alternative RNA processing generates different mRNAs, which can direct the synthesis of different polypeptides.

Question 32

Transcription in eukaryotes is generally influenced by enhancers just as in prokaryotes.

Question 33

When transcription factors interact with DNA, is the resulting genetic control typically positive or negative?

Question 34

Approximately 5% of the cytosine residues are methylated in the genome of any given eukaryote. In what way is DNA methylation related to genetic regulation?

Question 35

Regulation of RNA transport through the nuclear membrane is as common in prokaryotes as in eukaryotes.

Question 36

The CAAT (CAAT box) sequence appears to be critical to the ability of many eukaryotic promoters to facilitate transcription.

Question 37

Transcription factors are proteins with at least two functional domains-one that binds to DNA and one that binds to RNA polymerase or to other transcription factors.

Question 38

What are zinc fingers, and why are they frequently encountered in descriptions of genetic regulation in eukaryotes?

Question 39

The human metallothionein IIA gene (hMTIIA) is transcriptionally regulated through the interplay of regulatory elements and transcription factors. What is the function of this gene, and how is it regulated by environmental circumstances?

Question 40

An upstream activator sequence (UAS) can function at variable distances and in either orientation. However, it differs from an enhancer in that it cannot function downstream of the transcription starting point.

Question 41

One of the earliest steps in the RNAi pathway involves the association of siRNA or miRNA molecules with an enzyme complex composed mainly of reverse transcriptase.

Question 42

The term spliceopathy would be a reasonable term to signify a genetic condition caused by a defect in the regulation of RNA splicing.

Question 43

Alternative RNA processing can result in different mRNAs that start with different exons.