Biology subjects

Guiziou, S.

Publications and source records attributed to Guiziou, S..

9 recordsLinked to original sources

bioRxiv2026

Rational design of T-DNA vectors enables predictable, single-copy integration in Arabidopsis thaliana

Agrobacterium-mediated transformation is the dominant method for plant transgenesis, yet it frequently produces multi-copy, structurally complex T-DNA insertions associated with transgene silencing, unpredictable expression, and genome instability. Here, leveraging a high-throughput phenotypic reporter, we systematically dissect how T-DNA vector architecture, plasmid biology, and regulatory element choice shape transformation outcomes in Arabidopsis thaliana. We discover a pronounced trade-off between transformation efficiency and T-DNA copy number, uncovering the virulence enhancing overdrive sequence as a major determinant of this relationship. Guided by these insights, we engineered a new T-DNA vector that balances efficient transformation with predominantly single-copy integration. Additionally, we replaced viral elements, such as the widely used CaMV 35S promoter, with Arabidopsis-derived regulatory elements to minimise undesired enhancer effects, and developed a streamlined workflow for efficient T-DNA insertion mapping in the genome. Together, these advances form the T1 vector series, an Arabidopsis-optimised T-DNA vector system that enables clean, single-copy, and readily mappable transgene integration with predictable expression in the first generation after transformation.

plant biology↗

bioRxiv2025

Characterization of recombinase-based genetic parts and circuits using nanopore sequencing

Recombinases are versatile enzymes able to perform the precise insertion, deletion, and rearrangement of DNA and can act as a foundation for programmable genetic logic and memory. Fundamental to their use are accurate measurements of function. However, these are often laborious, time-consuming, and costly to collect. To address this, we developed a semi-automated workflow that combines low-cost liquid handling robotics, multiplexed long-read nanopore sequencing, and a supporting computational analysis tool to enable the high-throughput and detailed characterization of recombinase parts and circuits when used in a variety of contexts and organisms. Our approach overcomes the limitations of typically used fluorescence-based assays and is able to monitor temporal dynamics, observe structural changes at a nucleotide resolution, and unravel the internal workings of complex multi-state circuits. The ability to scale-up and automate genetic circuit characterization is an essential step towards more rigorous biological metrology that can support the construction of predictive models for efficiently engineering biology.

synthetic biology↗

bioRxiv2024

A history-dependent integrase recorder of plant gene expression with single cell resolution

During development, most cells experience a progressive restriction of fate that ultimately results in a fully differentiated mature state. Understanding more about the gene expression patterns that underlie developmental programs can inform engineering efforts for new or optimized forms. Here, we present a four-state integrase-based recorder of gene expression history and demonstrate its use in tracking gene expression events in Arabidopsis thaliana in two developmental contexts: lateral root initiation and stomatal differentiation. The recorder uses two serine integrases to mediate sequential DNA recombination events, resulting in step-wise, history-dependent switching between expression of fluorescent reporters. By using promoters that express at different times along each of the two differentiation pathways to drive integrase expression, we successfully tied fluorescent status to an ordered progression of gene expression along the developmental trajectory. In one snapshot of a mature tissue, our recorder was able to reveal past gene expression with single cell resolution. In this way, we were able to capture heterogeneity in stomatal development, confirming the existence of two alternate paths of differentiation.

synthetic biology↗

bioRxiv2022

An integrase toolbox to record gene-expression during plant development.

There are many open questions about the mechanisms that coordinate the dynamic, multicellular behaviors required for organogenesis. Synthetic circuits that can record in vivo signaling networks have been critical in elucidating animal development. Here, we report on the transfer of this technology to plants using orthogonal serine integrases to mediate site-specific and irreversible DNA recombination visualized by switching between fluorescent reporters. When combined with promoters expressed during lateral root initiation, integrases amplified reporter signal and permanently marked all descendants. In addition, we have developed a suite of methods to tune the threshold for integrase switching, including: RNA/protein degradation tags, a nuclear localization signal, and a split-intein system. These tools improved the robustness of integrase-mediated switching with different promoters and the stability of switching behavior over multiple generations. This integrase toolbox can be used to build history-dependent circuits to decode the order of expression during organogenesis in many contexts.

synthetic biology↗

bioRxiv2020

A single cell view of the transcriptome during lateral root initiation in Arabidopsis thaliana

Root architecture is a major determinant of fitness, and is under constant modification in response to favorable and unfavorable environmental stimuli. Beyond impacts on the primary root, the environment can alter the position, spacing, density and length of secondary or lateral roots. Lateral root development is among the best-studied examples of plant organogenesis, yet there are still many unanswered questions about its earliest steps. Among the challenges faced in capturing these first molecular events is the fact that this process occurs in a small number of cells with unpredictable timing. Single-cell sequencing methods afford the opportunity to isolate the specific transcriptional changes occurring in cells undergoing this fate transition. Using this approach, we successfully captured the transcriptomes of initiating lateral root primordia, and discovered many previously unreported upregulated genes associated with this process. We developed a method to selectively repress target gene transcription in the xylem pole pericycle cells where lateral roots originate, and demonstrated that expression of several of these targets was required for normal root development. We also discovered novel subpopulations of cells in the pericycle and endodermal cell files that respond to lateral root initiation, highlighting the coordination across cell files required for this fate transition. One sentence summarySingle cell RNA sequencing reveals new molecular details about lateral root initiation, including the transcriptional impacts of the primordia on bordering cells.

plant biology↗

bioRxiv2019

Exploring the design space of recombinase logic circuits.

Logic circuits operating in living cells are generally built by mimicking electronic layouts, and scale-up is accomplished using additional layers of elementary logic gates like NOT and NOR gates. Recombinase-based logic, in which logic is implemented using DNA inversion or excision, allows for highly efficient, compact and single-layer design architectures. However, recombinase logic architectures depart from electronic design principles, and gate design performed empirically is challenging for an increasing number of inputs. Here we used a combinatorial approach to explore the design space of recombinase logic devices. We generated combinations and permutations of recombination sites, genes, and regulatory elements, for a total of ~19 million designs supporting the implementation of all 2- and 3-input logic functions and up to 92% of 4-input logic functions. We estimated the influence of different design constraints on the number of executable functions, and found that the use of DNA inversion and transcriptional terminators were key factors to implement the vast majority of logic functions. We provide a user-friendly interface, called RECOMBINATOR (http://recombinator.lirmm.fr/index.php), that enable users to navigate the design space of recombinase-based logic, find architectures implementing a specific logic function and sort them according to various biological criteria. Finally, we define a set of 16 architectures from which all 256 3-input logic functions can be derived. This work provides a theoretical foundation for the systematic exploration and design of single-layer recombinase logic devices.\n\n\n\nO_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=55 SRC=\"FIGDIR/small/711374v2_ufig1.gif\" ALT=\"Figure 1\">\nView larger version (14K):\norg.highwire.dtl.DTLVardef@799feborg.highwire.dtl.DTLVardef@f22dc2org.highwire.dtl.DTLVardef@19a1d10org.highwire.dtl.DTLVardef@ea3b9a_HPS_FORMAT_FIGEXP M_FIG C_FIG

synthetic biology↗

bioRxiv2019

Rational programming of history-dependent logic in cellular populations.

Genetic programs operating in an history-dependent fashion are ubiquitous in nature and govern sophisticated processes such as development and differentiation. The ability to systematically and predictably encode such programs would advance the engineering of synthetic organisms and ecosystems with rich signal processing abilities. Here we implement robust, scalable history-dependent programs by distributing the computational labor across a cellular population. Our design is based on recombinase-driven DNA scaffolds expressing different genes according to the order of occurrence of inputs. These multicellular computing systems are highly modular and any program can be built by differential composition of strains containing well-characterized logic scaffolds. We developed an automated workflow that researchers can use to streamline program design and optimization. We anticipate that the history-dependent programs presented here will support many applications using cellular populations for material engineering, biomanufacturing and healthcare.\n\nOne Sentence SummarySystematic and automated frameworks for implementing robust history-dependent genetic programs in cellular populations.

synthetic biology↗

bioRxiv2018

Hierarchical composition of reliable recombinase logic devices.

We provide a systematic framework for engineering reliable recombinase logic devices by hierarchical composition of well-characterized, optimized recombinase switches. We apply this framework to build a recombinase logic device family supporting up to 4-input Boolean logic. This work will support the predictable engineering of several classes of recombinase devices to reliably control cellular behavior.

synthetic biology↗

bioRxiv2017

Scalable composition frameworks for multicellular logic

A major goal of synthetic biology is to reprogram living organisms to solve pressing challenges in manufacturing, environmental remediation, or healthcare. While many types of genetic logic gates have been engineered, their scalability remains limited. Previous work demonstrated that Distributed Multicellular Computation (DMC) enables the implementation of complex logic within cellular consortia. However, current DMC systems require spatial separation of cellular subpopulation to be scalable to N-inputs, and need cell-cell communication channels to operate. Here we present scalable composition frameworks for the systematic design of multicellular consortia performing recombinase-based Boolean or history-dependent logic, and integrating an arbitrary number of inputs. The theoretical designs for both Boolean and history-dependent logic are based on reduced sets of computational modules implemented into specific cellular subpopulations which can then be combined in various manners to implement all logic functions. Our systems mark a departure from previous DMC architectures as they do not require either cell-cell communication nor spatial separation, greatly facilitating their implementation and making them fully autonomous. Due to their scalability and composability, we anticipate that the design strategies presented here will help researchers and engineers to reprogram cellular behavior for various applications in a streamlined manner. We provide an online tool for automated design of DNA architectures allowing the implementation of multicellular N-inputs logic functions at: http://synbio.cbs.cnrs.fr/calin.

synthetic biology↗