Science - USA (2022-01-21)

Zhuet al.,Science 375 , eabg9765 (2022) 21 January 2022 5 of 11

B External inducers switch cells between states

A Modulating TF stability destabilizes specific states and allows irreversible transitions

0 12

TF A

0

12

TF B

0 25

TF A

0

25

TF B

0 25

TF A

0

25

TF B

Modeling

High TMP Low TMP High TMP

Nullclines

Stable fixed point

Unstable fixed point

Separatrix

Attractor basins

Simulated cells

= 0.8, = 20

Experiment

= 0.4, = 10 = 0.8, = 20

A-only

B-only A + B

OFF

0

20

40

60

80

100

% of cells

High TMP Low TMP High TMP

Initial state Day 0 Day 9 Day 18 Day 27 Day 36 Day 45

A + B

Day 0 Day 3 Day 6 Day 9 Day 18

Type II tristability regime

High TMP

• Dox + Dox - Dox


• 4-OHT + 4-OHT - 4-OHT

High TMP Low TMP High TMP

A-only

High TMP

• 4-OHT + 4-OHT - 4-OHT

B-only

A + B

Initial state

High TMP

• Dox + Dox - Dox

Low TMP High TMP

A + B

Bistability regime

Low TMP

• Dox + Dox - Dox

Low TMP

• 4-OHT + 4-OHT - 4-OHT

A-only

B-only

Initial state Day 0 Day 3 Day 6 Day 9 Day 18

B

Dox

A

4-OHT

Fig. 4. MultiFate-2 supports modulation of state stability and allows
state switching.(A) Escape from the destabilized A+B state was irreversible,
as shown by both modeling and experiments that used MultiFate-2.1 cells.
Top: The model used here is symmetric and nondimensionalized, with rescaled
dimerization dissociation constantKd= 1 and Hill coefficientn= 1.5 (Box 1).
Thexandyaxes are total dimensionless concentrations of TF A and TF B,
respectively. Simulated cells on phase portraits were calculated using the Gillespie
algorithm ( 25 , 54 ). Note that in the nondimensionalized model, changing protein

stability is equivalent to multiplyingaandbwith the same factor (Box 1).

Bottom: Throughout the experiment, we added 100 nM AP1903. Exact concen-

trations of TMP are shown in fig. S9. (B) MultiFate-2.3 cells can be switched

between states by transient 4-OHT (25 nM) or Dox (500 ng/ml) treatment. In

all conditions, we added 100 nM AP1903. Exact concentrations of TMP are

shown in fig. S16. In all panels, initial A-only, B-only, and A+B cells

were sorted from a population of cells in different states. Each square repre-

sents the mean fractions of three biological replicates.

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