Gene Expression

Question 1

Name 3 diseases associate with mutations in DNA control elements

Answer 1

1. Thalassimas
2. Hemophilia B-leyden (bin laden…)
3. Fragile X

Question 2

What are the 2 classes of DNA activators and repressors?

Answer 2

Sequence specific DNA binding proteins

Co-factors (don’t bind directly to DNA)

Question 3

What are the 2 domains of DNA activators?

Answer 3

1. DNA Binding domain

2. Activation domain (ie cofactor binding domain)

Question 4

What are the 4 types of DNA binding domains?

Answer 4

1. Homeodomains (Helix turn helix)
2. Helix loop Helix
3. Zinc Finger
4. Leucine Zipper (bZIP)

Question 5

Name a disease that is associated with a mutation in a Homeodomains of a protein?

Answer 5

Crainiostynosis- early fusion of the skull. Mutation causes a gain of function

Question 6

Name a disease that is associated with a mutation in a zinc finger domain of a protein?

Answer 6

Androgen insensitivity syndrome

Question 7

Name a disease that is associated with a mutation in a Helix loop helix (bHLH) domain of a protein?

Answer 7

Waardenburg Syndrome type II- which is characterized by deafness and pigmentation defects.

Question 8

Why is heterodimerization of binding domains important?

Answer 8

It allows for “combinatorial control” or the ability to control many regions because of increased DNA binding ability of each protein monomer.

Question 9

Swi/SNF are examples of what kind of histone modifier?

Answer 9

ATP-dependent

Question 10

Do activating proteins recruit HATs or HDACs?

Answer 10

HATs

Question 11

What causes Rubinstein-Taybi Syndrome? What characterizes this disease?

Answer 11

CBP haploinsuficcency. CBP is a HAT.

Characterized by growth retardation, mental retardation, craniofacial dysmorphism, abnormally broad
thumbs and great toes.

Question 12

How does tamoxifen work?

Answer 12

It binds to estrogen receptors and prevents recruiting of HATs

Question 13

What allows NF-KB to enter the nucleus? How does Aspirin prevent inflammation?

Answer 13

IkB is bound to NF-kB, preventing entry to the nucleus. Ubiquination targets IkB for degradation. NF-kB enters.

Aspirin blocks the ubiquination of IkB

Question 14

How does B-catenin regulate the amount of transcription factors in a cell?

Answer 14

In high concentrations of WNT signaling, B-catenin is NOT phosphorylated. B-cat enters nucleus and activates WNT responsive genes.

Question 15

What regulates p53 and targets it for destruction?

Answer 15

MDM2

Question 16

How does CREB recruit CBP?

Answer 16

Once CREB is phosphorylated it recruits CBP (HAT) leading to transcription.