Suppressors

Question 1

What is a suppressor?

Answer 1

Two mutations that cancel each other out and revert the mutant back to WT

Question 2

What are the two classes of suppression?

Answer 2

True reversion
Pseudo reversion

Question 3

What are the two classes of pseudo reversion?

Answer 3

Intragenic
Extragenic

Question 4

What does a true reversion do?

Answer 4

Fixes genotype

Question 5

What does a pseudo reversion do?

Answer 5

Fixes phenotype

Question 6

A second indel fixing a Frameshift is what type of suppression?

Answer 6

Intragenic

Question 7

A second mutation fixing a mutation in FtsZ’s ATP binding pocket by further altering the pocket is what type of suppression?

Answer 7

Intragenic, different codon

Question 8

What is conformational suppression?

Answer 8

It restores an interaction or activity based on structure

Question 9

Is conformational suppression intragenic or extragenic?

Answer 9

Both

Question 10

Is conformational suppression gene or allele specific?

Answer 10

Both

Question 11

What the the types of conformational suppression?

Answer 11

RNA-RNA
Protein-DNA
Protein-protein

Question 12

What’s an example of RNA-RNA conformational suppression?

Answer 12

A mutated ribosome regains binding via another mutation

Question 13

What’s an example of protein-DNA conformational suppression?

Answer 13

A protein is mutated but then can binds to a mutated binding site

Question 14

What’s an example of protein-protein conformational suppression?

Answer 14

The lock and key example with the semicircles with various shapes carved into them

Question 15

What are the types of extragenic suppression?

Answer 15

Conformational
Informational
Bypass

Question 16

What’s an informational suppressor?

Answer 16

Changes how the mutation is read or decoded

Question 17

Is informational suppression gene or allele specific?

Answer 17

Allele specific only

Question 18

What are the types of informational suppressors?

Answer 18

Nonsense
Frameshift suppressors

Question 19

What is a nonsense suppressor?

Answer 19

Amber, ochre, opal are mutated tRNAs that compete with the STOP tRNA for binding

Fix premature STOP

Question 20

What’s a Frameshift suppressor?

Answer 20

The tRNA with codon CCCC that can pick up a G insertion to revert the reading frame

Question 21

What’s a bypass suppressor?

Answer 21

Suppresses the need for an altered gene or pathway
Can act on one gene with multiple mutations or multiple mutated genes in the same pathway

Question 22

Are bypass suppressors gene or allele specific?

Answer 22

Gene/pathway specific only

Question 23

What does over-expression do and how?

Answer 23

Allows ordering of genes in a pathway
If the pathway reverts to WT, the over-expressed gene is downstream

Question 24

What genes are informational suppressors?

Answer 24

Always tRNA genes