Topics 8-9 CRISPR technology (Doudna)

Question 1

How was CRISPR technology invented?

Answer 1

It came about through a basic research project aimed at how bacteria fight viral infection.

Note: restriction enzymes are also found accidentally when scientists were researching the bacteria’ ability to defend against bacteriophage (lambda phage)

Question 2

What is the function of CRISPR in bacterial cells?

Answer 2

Adaptive immune system

Question 3

What is an adaptive immune system? How does it differ from innate immune system?

Answer 3

(In human’s lymphatic system)
Innate immune system is non-specific, quickly summoned. It has limited diversity, has no memory, recognizes pathogens through molecular patterns, and is responsible for autoinflammatory disease.

Adaptive immune system is highly specific, slowly sommoned. It has a high diversity, possesses memory (the other cells are effectors), recognizes through antigen (humoral), and is responsible for autoimmune disease

Question 4

What is the RNA-contained protein that is responsible for degrading viral DNA?

Answer 4

Cas 9

Question 5

What does “harness” mean?

Answer 5

(literally) to put harness (strip of metal and leather to put on horse head) on animals to control them.
Ex: To harness a horse
(figurative) to control or make use of the force or strength of something to produce power or do something else.
Ex: By using solar panel, we can harness solar energy to produce electricity and heat.
Ex: We can harness Cas9’s function as a genetic technology.

Question 6

What distinguishes Cas9 from other genetic editing methods?

Answer 6

Scientists can us Cas9 with RNA probe (artificially produced) to pinpoint exact location for deletion or insertion of specific bits of DNA with incredible precision. For instance, if we make a oligonucleotide RNA with 10 nucleotides, the chance of repeating that sequence would be 1/4^10. Cas9 can break double-stranded DNA

In contrast, restriction enzyme, like EcoRI, recognizes every GAATTC/CTTAAG on the DNA, therefore, it will cut the DNA at every location that contains such sequence. Chance of repetition is 1/4^6

Question 7

What does CRISPR stand for?

Answer 7

Clustered regularly interspaced short palindromic repeats.

Question 8

How can RNA of Cas9 recognize bit of DNA from virus?

Answer 8

Matching sequence

Question 9

What is the basic mechanism of CRISPR?

Answer 9

Pluck out bit of DNA from virus -> insert into site called CRISPR on the DNA of bacterium (Vaccination card) -> transcribe inserted viral DNA to RNA -> integrate that RNA into Cas-family proteins -> sentinel for viral DNA