#48 Extrinsic noise of the target gene governs abundance pattern of feed-forward loop motifs

Md Sorique Aziz Momin (Bose Institute, Kolkata, India)

Tuesday, 01 Dec 21:15 - 22:00 CET

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Abstract

Title: Extrinsic noise of the target gene governs abundance pattern of feed-forward loop motifs

Author(s): Md Sorique Aziz Momin^a and Ayan Biswas^a

Affiliation(s): ^aBose Institute, Kolkata, India

Abstract: Feed-forward loop (FFL) is the only significant network motif in gene transcription regulatory network (GTRN) of E.coli and yeast. In an FFL, a master-regulator regulates another co-regulator, and both of them jointly regulate a target gene. This regulation of gene by a TF can be activation (repression) thus up-regulating (down-regulating), enhances (decreases)the production rate and thereby copy numbers of desired proteins. Now, if we allow all the possible combination of regulation considering three TFs/genes, we will get a total of 8 different types of FFL. These FFLs can be classified into two groups: coherent (C) and incoherent (I), each containing four patterns. Among the eight different FFLs, only C1  and I1 occurs much more frequently in real GTRN, but why? We have developed an analytical framework pointing out that the extrinsic noise of the target gene plays a crucial role that determines the relative abundant pattern of FFLs. We found out that extrinsic noise is maximum for C1 and I1 FFLs comparing with the rest. Our theoretical construct employs for a constant and variable signal population (S) considering two signal integration mechanism, additive (OR gate) and multiplicative (AND gate), a total of 32 combinations. This might be the possible reason behind their abundant nature in GTRN. Our results are substantiated by stochastic simulation.

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