Unit 1

Question 1

TATA box/initiator sequence

Answer 1

25-35 bases upstream of transcription start site. Determines site of transcription initiation. Directs RNA polymerase II binding. General transcription factors bind here.

Question 2

Promoter proximal elements

Answer 2

Approximately 200 bases upstream of start site and are ~20 bases long. Help regulate transcription and can be bound by transcription factors.

Question 3

Enhancers

Answer 3

Far upstream of start site. Can contain multiple control elements. Help regulate transcription rate.

Question 4

Beta thalassemia

Answer 4

Inherited anemia due to deficient production of beta globin by erythroid cells -> less mRNA -> less protein
Arises from mutation in DNA control elements.

Question 5

γβδ-thalassemia

Answer 5

Deletion of locus control region. Arises from mutation in DNA control elements.

Question 6

Hemophilia B Leyden

Answer 6

X-linked disorder affecting clotting. Problems with the DNA control element of IX gene–1% of factor IX production until puberty, then androgen receptor becomes active and helps increase it to 60%. Arises from mutation in DNA control elements.

Question 7

Fragile-X Syndrome

Answer 7

1 in 1500 males. Causes mental retardation, facial dysmorphia, and macroorchidism. CGG repeat at 5’ end of FMR1 Gene causes methylation and transcription repression. Arises from mutation in DNA control elements.

Question 8

Transcriptional Activators

Answer 8

Proteins coded by another gene to regulate transcription. Diffuse around nucleus and can affect multiple genes.

Question 9

Transcriptional Repressors

Answer 9

Proteins coded by another gene to regulate transcription. Diffuse around nucleus and can affect multiple genes.

Question 10

Sequence-specific DNA binding proteins

Answer 10

Bind to promoter or enhancer units. Interact directly with DNA by inserting helices into major groove.

Question 11

DNA co-factors

Answer 11

Do not bind directly to DNA. Bind to certain DNA binding proteins and impact transcription in this way.

Question 12

Domains of DNA binding proteins.

Answer 12

DNA binding domain:
Highly structured, folded to bind to DNA

Activation (or repression) domain:
Bind co-factors or general transcription factors

Question 13

Families of DNA-binding proteins

Answer 13

Homeodomain (helix turn helix)
Zinc Finger
Helix loop helix
Basic leucine zipper

Question 14

Homeodomain (helix turn helix)

Answer 14

Hox family, Pit1, Msx

Question 15

Zinc Finger

Answer 15

Estrogen receptor, androgen receptor, retinoic acid receptor

Question 16

Helix loop helix

Answer 16

MyoD, myogenin, Myf5

Question 17

Basic leucine zipper

Answer 17

c-fos and c-jun

Question 18

DNA Replication Disorders

Answer 18

Bloom Syndrome:
Mutation in RecQ helicase BLM
Werner Syndrome:
Mutation in RecQ helicase WRN
Meier-Gorlin:
Mutation in pre-replication complex

Question 19

Nucleotide Synthesis Inhibitors

Answer 19

Methotrexate
Fluorouracil
Hydroxyurea

Question 20

DNA Polymerase Inhibitors

Answer 20

Cytosine Arabinoside
Acyclovir
Ganciclovir
Foscarnet
Gemcitabine