suppression analysis

Question 1

what is suppression analysis

Answer 1

• first of create a mutation or have a know mutation
• create a second mutation which can restore the WT (phenotypic reversion)
• identify what kind of 2nd mutation

Question 2

3 way of reversion

Answer 2

1/ true reversion: transform back to wildtype
2/intragenic suppression: second mutation in the same gene and counter act the effect of the first mutation
3/extragenic mutation: mutation in a different gene that counter act the effect of the mutation

Question 3

How to identify type of suprresion

Answer 3

cross with a pure breed WT
true reversion ration 100% WT
intragenic: parental phenotype will have more
extragenic: 2:1:1 ratio but only when mu>50

Question 4

How does intragenenic suppression work

Answer 4

• Frameshift: restore the reading frame

- missense mutation: allow the protein to be folded correctly

Question 5

how does extragenic suppression work

Answer 5

• translational
• Physiological
• Protein - Protein interaction
• Gene expression

Question 6

how does extragenic suppression work translational

Answer 6

• the first mutation is a nonsense mutation, no tRNA leading to termination
• second mutation in tRNA, the charge tRNA bind with the stop codon allow translation to continue
• But it compete with normal release factor so only 4-30% effective

Question 7

how does extragenic suppression work Physiological

Answer 7

• parallel pathway, the second mutation lead to a gain of function, can also carry gene a task
• bypass of toxicity. gene product of a pathway is toxic without gene A. LOF in gene B > no toxic compound

Question 8

how does extragenic suppression work Protein - Protein interaction

Answer 8

• 1 mutation cannot make a active dimer

- 2 mutation compateble again, active dimer

Question 9

how does extragenic suppression work Protein - Gene expression

Answer 9

• both involve in transcription factor as regulator. GOF lead to cover both gene A and B role
• the mutation alone is likely wt