# Independent channels for miRNA biosynthesis ensure efficient static and dynamic control in the regulation of the early stages of myogenesis

## TL;DR

This study models the miRNA regulatory network in early myogenesis, revealing how independent biosynthesis channels and competition control molecular levels and enable rapid differentiation responses.

## Contribution

It provides a quantitative analysis of two independent miRNA biosynthesis pathways and their combined role in controlling early myogenesis, highlighting their necessity for efficient regulation.

## Key findings

- Optimal static control constrains kinetic parameters.
- Alternative transcription ensures rapid concentration shifts.
- Both channels are essential for circuit functionality.

## Abstract

Motivated by recent experimental work, we define and study a deterministic model of the complex miRNA-based regulatory circuit that putatively controls the early stage of myogenesis in human. We aim in particular at a quantitative understanding of (i) the roles played by the separate and independent miRNA biosynthesis channels (one involving a miRNA-decoy system regulated by an exogenous controller, the other given by transcription from a distinct genomic locus) that appear to be crucial for the differentiation program, and of (ii) how competition to bind miRNAs can efficiently control molecular levels in such an interconnected architecture. We show that optimal static control via the miRNA-decoy system constrains kinetic parameters in narrow ranges where the channels are tightly cross-linked. On the other hand, the alternative locus for miRNA transcription can ensure that the fast concentration shifts required by the differentiation program are achieved, specifically via non-linear response of the target to even modest surges in the miRNA transcription rate. While static, competition-mediated regulation can be achieved by the miRNA-decoy system alone, both channels are essential for the circuit's overall functionality, suggesting that that this type of joint control may represent a minimal optimal architecture in different contexts.