Gene Expression

Question 1

The DNA binding domain is located on the ___________ where as the DNA binding element is located on the ____________

Answer 1

Protein; DNA strand

Question 2

__________ is the most important mechanism for determining whether or not genes are expressed.

Answer 2

The first step, the transcription initiation

Question 3

What is the TATA box?

Answer 3

Determines transcription initiation and direct binding of RNA polymerase II

Question 4

Where is the site where general transcription factor’s bind?

Answer 4

The TATA box

Question 5

_____________ are generally located 200 base pairs upstream of the transcription site and help regulate in a cell-type specific manner. __________ also help regulate in a cell-type specific manner yet can be very far upstream or down stream from the promoter

Answer 5

Promoter proximal elements; enhancers

Question 6

Beta-Thalassemia is an inherited anemia caused by a mutation on the _____________, reducing the amount of __________

Answer 6

Beta-globin promoter; beta globin mRNA

Question 7

Why does the effects of hemophilic beta Leyden decrease in puberty?

Answer 7

The lack of clotting factor is affected by an inherited mutation in promoter of factor IX. At puberty, the androgen receptor becomes active and can bind to the promoter site through overlap.

Question 8

Fragile X syndrome is caused by an expansion in ___________ in the 5’ region, silencing the FMRI gene.

Answer 8

CGG repeats

Question 9

The two classes of activators and repressors are ________ and ____________

Answer 9

Sequence specific DNA binding proteins; Co-factors

Question 10

Sequence specific DNA binding proteins bind to ____________, inserting their alpha helixes in the ___________ of DNA, allows for contact between the amino acid chains and bases of the DNA

Answer 10

Promoter or enhancer elements; Major groove

Question 11

Co-factors bind to ______________

Answer 11

Sequence specific DNA binding proteins

Question 12

The _________ of DNA binding proteins is highly structured, conserved and folded where as the __________ is very unstructured until they bind to co-factors

Answer 12

DNA binding domain; activation domain

Question 13

Describe the structure of the homeodomain proteins (helix-turn-helix)

Answer 13

Has a 60 amino acid domain called a homeodomain; has 3 helices; the second two helices makes the helix-turn-helix motif

Question 14

Describe the structure of the zinc finger protein.

Answer 14

Made of four cystine residues/ or two cystine residues and two histone residues; the fingers recognize and bind to DNA; includes androgen, estrogen and glucocorticoid

Question 15

Describe the structure of the basic leucine receptor protein.

Answer 15

Has a helical structure which allows the protein to dimerize and form zippers; the tail of amino acids interacts with the DNA; involved in the growth and proliferation of cancer

Question 16

Describe the basic helix-loop-helix motif.

Answer 16

This is the basic leucine zipper protein with the loop.

Question 17

Craniosynostosis involved mutation in the __________, MSX2. The mutation has one amino acid mutation which causes the protein to bind more strongly to the DNA, causing hyperactive suture closing.

Answer 17

Homeodomain protein

Question 18

Androgen insensitivity syndrome, which causes feminization of the external genetalia at birth is caused by a mutation in the ______________

Answer 18

Zinc finger binding protein

Question 19

Waardenberg syndrom Type II, which causes deafness and pigment abnormalities is due to a mutation in the _________

Answer 19

Basic helix-loop-helix binding protein

Question 20

Leucine zipper binding proteins can demonstrate combinatorial control by forming __________ or ____________

Answer 20

homodimers; heterdimers

Question 21

The two classes of chromatin remodeling factors include __________ and ____________

Answer 21

DNA dependent ATPases(disrupt histones); HATs and HDACs (reversible)

Question 22

The N-termini of histone are rich in __________ residues.

Answer 22

Lysine

Question 23

What is a HAT?

Answer 23

Histone acetyltransferase; acetylates the n-termini of histones and neutralize the positively charged ends of the lysine rich tail; co-activator

Question 24

What is a HDAC?

Answer 24

Histone deacetylases; removes acetyl groups from the histones and aids in DNA remaining wound; co-repressor

Question 25

In Rubinstein-Taybi syndrome, which involves growth and mental retardation and craniofacial dimorphism, there is a mutation in the _____________ which is a ___________

Answer 25

CREB binding protein; HAT

Question 26

_________ is the more accessible form of chromatin, whereas __________ is always repressed because the DNA is inaccessible

Answer 26

Euchromatin; Heterochromatin

Question 27

The conformation of the DNA-binding protein can be altered by ligand binding such as when __________ transcription factors bind to the steroid hormone.

Answer 27

Zinc finger

Question 28

__________ is normally held in the cytoplasm by binding to an inhibitor, yet when the inhibitor is phosphorylated and degraded, this protein gets the nuclease localization signal and performs activity involved in inflammation

Answer 28

NFkB

Question 29

High intracellular calcium activate calcinurin’s phosphotase activity, dephosphorylating _______, allowing it to travel into the nucleus, where is affects transcription of genes involved in immune response in heart function.

Answer 29

NFAT

Question 30

In the absence of Wnt signaling, ___________ is targeted for degradation.

Answer 30

beta-catenin

Question 31

In the presence of Wnt signaling, the Axin-APC-GASK3 is destabilized, preventing_____________

Answer 31

The phosphorylation of beta-catenin

Question 32

p53 is down regulated by binding to the ____________ which masks its activation domain and target it for destruction

Answer 32

MDM2

Question 33

__________ negatively regulate DNA by causing a lack of a basic domain

Answer 33

ID proteins