5. Gene Expression

Question 1

Six sites of Gene Control

Answer 1

1. Transcription
2. RNA Synthesis
3. RNA Transport and localization control
4. Translation
5. mRNA degradation
6. Protein activity control

Question 2

DNA Binding proteins’ binding position

Answer 2

The grooves
- Major groove / Minor groove
The groups in the bases that are not involved in inter-base H bonds

Question 3

Types of DNA binding proteins

Answer 3

• Helix-turn-Helix
• Homeodomain
• Leucine Zipper
• Beta sheet DNA recognition protein
• Zinc Finger proteins
• Helix-loop-Helix proteins

Question 4

Motif

Answer 4

A supersecondary structure of a protein / Nucleic Acid

Question 5

Helix-turn-helix Protein

Answer 5

• Found commonly in Eukaryotes and Prokaryotes
• Two helices linked by a short chain
• More “c-terminus” helix is the recognition helix
• Recognition helix fits into the major groove

Question 6

Homeodomain protein

Answer 6

• First discovered in Drosophila / regulating homeotic selector genes
• Three helices
• 3, is the recognition (C terminus)
• N terminus of protein binds to DNA
• Three helices held together by hydrophobic interaction

Question 7

Leucine Zipper

Answer 7

• Two separate monomers
• Identical - but mirror image
• Two helices joined together to form a coil
• Two held together by hydrophobic interactions
• Dimerization interface - where it’s linked
• Contacts major grooves

Question 8

Beta sheet DNA recognition proteins

Answer 8

• Two stranded Beta sheets
• Recognize major groove
• Transcription regulators

Question 9

Zinc Finger Proteins

Answer 9

A helix (C) and a beta sheet(N) held together by a zinc atom.
- Forms a chain - Not just one complex but a protein that is long and binds to a wide area of DNA

Question 10

Helix loop helix protein

Answer 10

Related to Leucine zipper

• Two protein molecules
• a helix connected by a loop to a second, longer helix
• Dimerization surface formed by the upper, short helices