Temperature Control of Fimbriation Circuit Switch in Uropathogenic Escherichia coli: Quantitative Analysis via Automated Model Abstraction
Figure 2
Type 1 fimbriae genetic regulatory network—the fim switch circuit.
Structural fimbriae subunits are encoded by fimA and other downstream genes, which are transcribed when the fim switch is in the ON position (as shown here – also see Figure 1). Recombinases and
bind to
/
and invert the switch with different rates (
is strongly biased in the ON-to-OFF direction, while
is close to fair). A small protein,
, acts in a temperature-dependent manner and represses the expression of the two recombinases.
stimulates and inhibits switching based on its occupancy of three
sites, while its expression is also repressed by
.
is required for any observable phase variation as it plays a structural role during switching through its ability to produce sharp bends in the DNA.