Biology subjects

Stankes, A. C.

Publications and source records attributed to Stankes, A. C..

2 recordsLinked to original sources

bioRxiv2025

Establishing a standardized genetic toolkit for the radiation-resistant extremophile Deinococcus radiodurans

Deinococcus radiodurans is a highly radiation-resistant extremophile with potential for biomanufacturing and bioremediation in harsh environments, including extraterrestrial settings. However, genetic engineering in this organism has been constrained by limited genetic tools. Here, we establish a comprehensive genetic toolkit for D. radiodurans that enables tunable gene regulation with genome-engineering tools. We have standardized a library of 36 constitutive promoter sequences sourced from the native D. radiodurans genome and from synthetic sources, spanning 45-fold range gene expression in the context of plasmids. We have also identified 136 variants of ribosome binding sites (RBS), variants using a high-throughput screen for precise translational control across a 963-fold range of expression when used in our plasmid-based system. Additionally, we have developed a codon-optimizer script that we leverage to improve the function of four fluorescent proteins in D. radiodurans. Next, we characterized 9 small molecule-inducible promoter systems, and identified four key inducible promoter systems that achieve between 3-fold and 12-fold signal amplification, as well as titratability across induction concentrations in D. radiodurans. To engineer the D. radiodurans genome, we present a novel method for gene integrations, compatible with de novo sequences, up to 3kB in length, doing so with 87% efficiency. Lastly, we repurpose the RNA-directed nuclease, TnpB, as a novel post-transcriptional tool for programmable gene repression analogous to CRISPRi-based systems, and this tool can achieve up to 70% repression of its target. Collectively, this toolkit provides modular, standardized components for both plasmid engineering and chromosomal engineering in D. radiodurans to improve its genetic tractability and to facilitate its deployment. TOC Image O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=149 SRC="FIGDIR/small/658681v1_ufig1.gif" ALT="Figure 1"> View larger version (29K): org.highwire.dtl.DTLVardef@c961deorg.highwire.dtl.DTLVardef@1386776org.highwire.dtl.DTLVardef@10977aorg.highwire.dtl.DTLVardef@1490931_HPS_FORMAT_FIGEXP M_FIG C_FIG

bioengineering↗

bioRxiv2023

Rewiring native post-transcriptional carbon regulators to build multi-layered genetic circuits and optimize engineered microbes for bioproduction

As the bioprocessing and synthetic biology spaces rapidly expand, post-transcriptional regulation is emerging as driver for maximizing signal response rate and for minimizing cost per protein within cells. Designing robust post-transcriptional control systems that have precise tunability and can achieve diverse regulatory outcomes are paramount to advance the field. Herein, we develop a new approach for engineered post-transcriptional control in bacteria by rewiring a native regulatory system in Escherichia coli, the Carbon Storage Regulatory (Csr) Network, to create tunable, complex genetic circuits. First, by co-opting native components of the Csr Network to regulate translation of a target mRNA transcript, we establish a Csr-regulated Buffer Gate. Next, by rationally engineering the interactions between our synthetic construct and the native components of the Csr Network, we expand our original design into a genetic toolbox of 12 Buffer Gates that achieve precise tunability across a 10-fold range of target gene expression. Subsequently, to further regulatory capabilities using this approach, we develop a Csr-regulated NOT Gate through engineering a Csr-activated sequence into our synthetic constructs. We then build upon the Csr Buffer and Not Gates to create post-transcriptional dual input Boolean OR, NOR, AND and NAND Logic Gates, as well as a genetic pulse circuit. As a third step, we demonstrate portability of our Csr-regulated Buffer Gates into three industrially relevant bacteria by recapitulating Buffer Gate activity simply by leveraging the conserved homologous Csr Network in each species. Lastly, as a demonstration of downstream application, we apply our system to a proof-of-concept synthetic mevalonate pathway. Using our engineered constructs, we optimize mevalonate production in E. coli resulting in a three-fold increase in production relative to a transcriptionally controlled mevalonate pathway. As a whole, we establish a novel approach to rewire post-transcriptional regulatory networks for complex bacterial computation that can be utilized for efficient bioproduction in engineered microbes.

bioengineering↗