Regulation: Virulence factors

Question 1

How do you find non coding genes in the genome?

Answer 1

Look for transcription signals, conserved sequences

Question 2

How can antisense type RNA regulate transcription?

Answer 2

Inhibiting by stopping ribosome from binding, inducing decay by being associated with RNase, activating translation by changing structure of mRNA (which exposes ribosome binding site), inhibiting decay. Can also activating translation by inhibiting proteins that stop translation

Question 3

What is the sRNA helper protein?

Answer 3

Hfq - can accelerate binding between sRNA and mRNA by having binding sites for both

Question 4

How does viruelence regulation look in v. cholerae?

Answer 4

Its controlled by quorum sensing. When theres low cell density, biofilm and virulence factors will be upregulated. LuxO-P gets phosphorylated which induces transcription of Qrr sRNAs, which repress HapR (associated with dispersal related T6SS) and induce AphA which in turn induce expression of biofilm genes. If theres high cell density they dont get phosphorylated, so HapR is not repressed. Biofilm genes are not induced; T6SS is induced instead

Question 5

How does viruelence regulation look in a. aureus?

Answer 5

Also quorum sensing - senses AIP. Low cell density leads to colonization and adhesion. High cell density activates toxicity

Question 6

How does viruelence regulation look in listeria?

Answer 6

By RNA thermometer - in the right temperature (body) PrfA is induced, and PrfA in turn turns on virulence factors

Question 7

What are RNA binding proteins?

Answer 7

Proteins that bind to GGA sequence on mRNA which can either stop 30S ribosome from binding (repress) or make Shine-Dalgarno available for binding (induce)