posted on 2023-08-18, 19:44authored byAna K. Velazquez Sanchez, Bjarne Klopprogge, Karl-Heinz Zimmermann, Zoya Ignatova
Predictable and controllable
tuning of genetic circuits to regulate
gene expression, including modulation of existing circuits or constructs
without the need for redesign or rebuilding, is a persistent challenge
in synthetic biology. Here, we propose rationally designed new small
RNAs (sRNAs) that dynamically modulate gene expression of genetic
circuits with a broad range (high, medium, and low) of repression.
We designed multiple multilayer genetic circuits in which the variable
effector element is a transcription factor (TF) controlling downstream
the production of a reporter protein. The sRNAs target TFs instead
of a reporter gene, and harnessing the intrinsic RNA-interference
pathway in E. coli allowed for
a wide range of expression modulation of the reporter protein, including
the most difficult to achieve dynamic switch to an OFF state. The
synthetic sRNAs are expressed independently of the circuit(s), thus
allowing for repression without modifying the circuit itself. Our
work provides a frame for achieving independent modulation of gene
expression and dynamic and modular control of the multilayer genetic
circuits by only including an independent control circuit expressing
synthetic sRNAs, without altering the structure of existing genetic
circuits.