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BACA THEODOR-STEFAN and SINIAVSCHI RADUMASTER ITEMS 2012
FEED-FORWARD LOOP CENTRAL DATABASE
Based on the article: STRUCTURE AND FUNCTION OF THE FEED-FORWARD LOOP NETWORK MOTIF by S. Mangan and U. Alon
Transcription factor X regulates transcription factor Y, and both jointly regulate Z. Sx and Sy are the inducers of X and Y, respectively. The action of X and Y is integrated at the Z promoter with a cis-regulatory input function , such as AND or OR logic.
Simple regulation of Z by Xand Y.
Feed-forward loop (FFL) is a motif, consisting in a three-gene pattern composed of two input transcription factors. Each of the three interactions in the FFL can be either activating or repressing (coherent or incoherent).
What is a FEED-FORWARD LOOP?
• Decide from fluctuating signal• Filter out pulses• Respond to persistent stimulations• Rapidly shut down
• Easly reverse• Initially reacts strongly• Later comes back to intermediate levels
COHERENT and INCOHERENT FFL type
Coherent Type-1 FFL – AND logic
Sx appear, X rapidly changes to X*
X* binds to gene Z, but cannot activate it
X* binds to gene Y, and begins to transcript it
Z begins to be expressed after Ton time, when Y* crosses the activation threshold Kyz
The FFL Database
An user-friendly web app that integrates feed forward loops so scientists and other enthusiasts could use the results for educational and scientifical purposes.
The FFL Database
An user-friendly web app that integrates feed forward loops so scientists and other enthusiasts could use the results for educational and scientifical purposes.
Methods of FFL Database
Search where we can get information about the regulatory networks
Get from the information about the regulation by Transcription Factors.
Construct an algorithm to extract the FFL motives different organisms regulatory networks.
Make a hierarchical clasiffication of FFLs elements.
Make a clasiffication acording to the origin of the signal that TFs sense.
Search for differences betwen the data on each position of the FFLs making statistical tests to validate significance.
CONCLUSIONS
Incoherent FFLs – sign-sensitive accelerators.
Coherent FFLs – sign-sensitive delays.
Some FFL occur more often than the others.
Observe how TFs that detect different-origin signals compose
Observe the dinamics on the TRN looking for the formation of specific topological structure, FFL
Search for significative differences on the data by statistical tests on each position of the FFLs.