Biology Reference
In-Depth Information
A
Notch
EGFR
Su(H)
ERK
YAN
MAE
PNT-P2
PNT-P1
miR-7
Target genes
Inducing differentiation
B
PNT-P1
YAN
PNT-P1
YAN
YAN
PNT-P1
miR-7
PNT-P1
miR-7
YAN
miR-7
miR-7
Figure 9.6
The YAN network. (A) The network is constituted by transcription
factors (blue)
YAN, Pnt-P1
,
Pnt-2
, the miRNA
miR-7
(red), protein-interactors
(green)
MAE
and
ERK
, and inputs from the
Notch
and
EFGR
signaling pathways
(purple). The output of the network is the transcriptional regulation of target genes
(box) required for differentiation. (B) Coupled FFLs and double-negative FFLs exist in
the network. Three three-node FFLs linking
YAN
,
Pnt-P1
, and
miR-7
are interlocked
(left, in black). These three FFLs are shown separately (in blue).
compared to simple regulation circuits, such FFLs provide redundancy.
Third, they would act as persistence detectors that only transduce stable
changes in the activity of the upstream node. If the FFL is structured where
the upstream TF activates and the miRNA represses the target, then the
miRNA would set a threshold, assuring that unless a given level of TF
activity is achieved, the downstream target is not affected.
Theoretical studies support the notion that FFLs containing miRNAs
could provide robustness to the expression of miRNA targets (
Hornstein
and Shomron, 2006
). A quantitative comparison of small RNA-based and
