E.coli Lecture 2

Question 1

What is H-NS?

Answer 1

Nuceloid associated protein and repressor of transcription

Question 2

What is a nucleoid

Answer 2

Dynamic structure: DNA replication + segregation + transcription + translation

Question 3

How is H-NS structured?

Answer 3

N-terminal: dimerization domain
C-terminal: DNA binding domain

Question 4

What does H-NS bind to?

Answer 4

Binds to AT rich (HGT) DNA with hook motif

Question 5

What is HGT DNA rich in?

Answer 5

AT regions

Question 6

How can H-NS repress transcription

Answer 6

Can block DNA binding by RNA poly
Can block elongation of transcription

Question 7

How can H-NS complexes on the DNA be disrupted?

Answer 7

By transcription
By specific transcription regulators

Question 8

What do NAPs do?

Answer 8

Organize DNA (like histones) DNA is supercoiled

Question 9

H-NS can form which structures?

Answer 9

A filament (only bound to 1 DNA) or a bridge (bound between 2 DNA)
Filament blocks only RNAP but not translation elongation (if Transcription regulator binds)
Bridge blocks both but not transcription regulators

Question 10

What is LeuO and what does it do?

Answer 10

Transcription regulator (antagonist to H-NS)
induces virulence
induces CRISPER/Cas
induces adherence …

Question 11

LTTR (transcription regulators) examples

Answer 11

LeuO, BglJ (preference for AT rich region, and antagonist to H-NS)