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Effects of microRNA-mediated negative feedback on gene expression noise

Adhikary, R and Roy, A and Jolly, MK and Das, D (2023) Effects of microRNA-mediated negative feedback on gene expression noise. In: Biophysical Journal, 122 (21). pp. 4220-4240.

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Official URL: https://doi.org/10.1016/j.bpj.2023.09.019


MicroRNAs (miRNAs) are small noncoding RNAs that regulate gene expression post-transcriptionally in eukaryotes by binding with target mRNAs and preventing translation. miRNA-mediated feedback motifs are ubiquitous in various genetic networks that control cellular decision making. A key question is how such a feedback mechanism may affect gene expression noise. To answer this, we have developed a mathematical model to study the effects of a miRNA-dependent negative-feedback loop on mean expression and noise in target mRNAs. Combining analytics and simulations, we show the existence of an expression threshold demarcating repressed and expressed regimes in agreement with earlier studies. The steady-state mRNA distributions are bimodal near the threshold, where copy numbers of mRNAs and miRNAs exhibit enhanced anticorrelated fluctuations. Moreover, variation of negative-feedback strength shifts the threshold locations and modulates the noise profiles. Notably, the miRNA-mRNA binding affinity and feedback strength collectively shape the bimodality. We also compare our model with a direct auto-repression motif, where a gene produces its own repressor. Auto-repression fails to produce bimodal mRNA distributions as found in miRNA-based indirect repression, suggesting the crucial role of miRNAs in creating phenotypic diversity. Together, we demonstrate how miRNA-dependent negative feedback modifies the expression threshold and leads to a broader parameter regime of bimodality compared to the no-feedback case. © 2023 Biophysical Society

Item Type: Journal Article
Publication: Biophysical Journal
Publisher: Biophysical Society
Additional Information: The copyright for this article belongs to the Authore.
Department/Centre: Division of Interdisciplinary Sciences > Centre for Biosystems Science and Engineering
Date Deposited: 03 Dec 2023 09:15
Last Modified: 03 Dec 2023 09:15
URI: https://eprints.iisc.ac.in/id/eprint/83470

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