Lecture 14 Flashcards
(62 cards)
what is the goal of transcription regulation
to maintain internal environment and survive
parts of the lac promoter
cap…rna binding site…lac O…shine dalgaro…start codon
where does positive and negative regulation in response to glucose happen
the lac promoter
why does lactose bind to the repressor
so it cant bind to lac O and prevent RNA pol from binding
types of transcription regulation
2 component system, quorum sensing, attenuation and lamdda phage
2 component pathway
let bacteria respond to external stimuli
-the receptor will get a signla and autophosphorylate on a histidine side chain
-the receptor sends phosphate to response regulator (protein) whihc is a DNA binding protein that will regulate transcription
how do ecoli respond to changes in the osmotic environment?
they use omp c and omp f porin proteins to limit the influx of solutes
porin protein
form pores in the outer membrane allowing molecules/ water to go in and out
omp c
narrower than omp f
-less molecules will flow causing the cell to stop shrinking
EnvZ receptor sensory kinase
change shape and activity to respond to osmotic pressure by increasing osmolarity and kinase activity
increase osmolarity
increase molecules in external environment which will in turn decrease water potential outside bacteria cell
how does EnvZ work with omp c and f
it will phosphorylate omp r and omp r will then regulate osmolarity genes
-the genes are omp c and f
-EnvZ has to activate omp c and f using omp r
-these are genes that alter the cells permeability
increase osmolarity response
use omp c to close gates in membrane so solute doesn’t enter
-very salty
decreasing osmolarity response
omp f will open the gates bc the environment is less salty
How many omp r site do c and f have
many
high affinity
bind tightly
-omp r doesnt need to be phosphorylated to bind
-omp f
omp r gets phosphorylated when?
when it needs to bind to sites of high and low affinity bc it also has to bind downstream (low affinity) to block transcription of omp F and turn on C
what happens to kinase when omp r is unphosphorylated
it doesnt change shape
what else can omp r control
pathogenesis
-only if in proper osmotic conditions and host environment
pathogenesis pathway
phosphorylated omp r goes to Ssra with will phosphorylate SsrB and then phosphorylate the pathogenesis gene
-these genes ARE NOT omp c or f
fusing photosynthetic light sensory to EnvZ
when omp r phosphorylates to omp c it will trigger lac Z (reporter gene) and we will see a black output
-this proves that omp c drives lac Z transgene
-turns bacteria into photographic film
collective bacteria behaviors
virulence factors, biofilm, antibiotic production and bioluminescense
autoinducer
secreted by bacteria, increase bacteria increase autoinducers
-at high concentrations they can enter cells and regulate genes
what binds to autoinducer
lux R
-targets gene activation
