Module 2 - Part 2

Question 1

Gene editing

Answer 1

A method used to alter an organism’s DNA seq by leveraging the cell’s DNA repair mechanism
- correct mutations
- insert DNA seq
- remove DNA seq

Question 2

Single stranded breaks (SSBs)

Answer 2

DNA repair mech:
- base excision repair
- nucleotide excision repair
Use template strand to replace cut out base

Question 3

Double stranded breaks (DSBs)

Answer 3

Homologous recombination (HR)
- uses homologous chromosome as template to fill in missing nucleotide
Non-homologous end joining (NHEJ)
- no template available, ends ligate together

Question 4

Gene editing uses a…

Answer 4

• recombinant enzymes to cleave/alter DNA seq such as
  1. zinc finger nucleases (ZFN)
  2. transcription activator-like effector nucleases (TALENS)
  3. CRISPR

Question 5

FOK1

Answer 5

a non-specific restriction enzyme that can only function as a dimer

Question 6

zinc finger

Answer 6

domain binds 3 nucleotides together at a time
- have 3-4 ZFs in a ZFN

Question 7

TALEs

Answer 7

function similar to ZF but only bind to 1 nucleotide at a time
- more easily customizable

Question 8

Dimerization of FOK1 results in…

Answer 8

one double stranded cut
- to replace w a new DNA seq you must use 4 ZFNs/TALENs

Question 9

CRISPR

Answer 9

clustered regularly interspaced short palindromic repeats
- bacteriophage DNA is cleaved by CAS 1/2
- integrated into bacterial genome in the interspaced regions

Question 10

CAS9

Answer 10

crispr-associated protein 9
- nuclease that cleaves bacteriophage DNA to prevent bacterial cell from protection
- bacterial immune system
- transcribe bacteriophage DNA elements into RNA if re-encountered
- RNA forms complex w CAS9 and cleaves DNA to block infection