Construction of a Genetic Toggle Switch in Escherichia coli

1
Construction of a Genetic Toggle Switch in
Escherichia coli

• All diagrams except the for the detailed switch
  diagram taken from
• Gardner, T.S., Cantor, C.R. and Collins, J.J.
  (2000)Construction of a Genetic Toggle Switch in
  Escherichia coli Nature 403 (6767) 339-343

2
Design

• U concentration repressor 1
• V concentration repressor 2
• a effective rates of synthesis
• ß and ? cooperativity of repressors

3
Detail
4
Specifications

• In absence of inducer,
• only one promoter
• should be effectively
• active
• Addition of inducer (eg.
• IPTG or thermal pulse)
• should trigger switching
• to desired state

5
Product

• 3 Promoter
• systems
• Low State
• PLs1con (CI)
• (Stronger)
• PLtetO-1 (TetR)

v
u

• High State
• Ptrc-2 (LacI)

6
Characteristics
? cooperativity of IPTG binding K
dissociation constant
7
Pros Cons .

• Is completely stable in both states
• Can be switched between states easily
• Small construct so products can be placed
  downstream

• Requires protein degradation so takes a LONG time
  to switch between states
• IPTG cannot be removed from environment after
  induction