Florence Jay

Last Name

Jay

First Name

Florence

ORCID

0000-0001-7353-8299

Organisational unit

03876 - Voinnet, Olivier / Voinnet, Olivier

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Publications 1 - 9 of 9

A contemporary reassessment of the enhanced transient expression system based on the tombusviral silencing suppressor protein P19
Jay, Florence; Brioudes, Florian; Voinnet, Olivier (2023)
The Plant Journal
Transient transgenic expression accelerates pharming and facilitates protein studies in plants. One embodiment of the approach involves leaf infiltration of Agrobacterium strains whose T-DNA is engineered with the gene(s) of interest. However, gene expression during 'agro-infiltration' is intrinsically and universally impeded by the onset of post-transcriptional gene silencing (PTGS). Nearly 20 years ago, a simple method was developed, whereby co-expression of the tombusvirus-encoded P19 protein suppresses PTGS and thus enhances transient gene expression. Yet, how PTGS is activated and suppressed by P19 during the process has remained unclear to date. Here, we address these intertwined questions in a manner also rationalizing how vastly increased protein yields are achieved using a minimal viral replicon as a transient gene expression vector. We also explore, in side-by-side analyses, why some proteins do not accumulate to the expected high levels in the assay, despite vastly increased mRNA levels. We validate that enhanced co-expression of multiple constructs is achieved within the same transformed cells, and illustrate how the P19 system allows rapid protein purification for optimized downstream in vitro applications. Finally, we assess the suitability of the P19 system for subcellular localization studies - an originally unanticipated, yet increasingly popular application - and uncover shortcomings of this specific implement. In revisiting the P19 system using contemporary knowledge, this study sheds light onto its hitherto poorly understood mechanisms while further illustrating its versatility but also some of its limits.
Correction: The Arabidopsis miR472-RDR6 Silencing Pathway Modulates PAMP- and Effector-Triggered Immunity through the Post-transcriptional Control of Disease Resistance Genes
Boccara, Martine; Sarazin, Alexis; Thiébeauld, Odon; et al. (2015)
PLoS Pathogens
A pectin acetyl‐transferase facilitates secondary plasmodesmata formation and RNA silencing movement between plant cells
Jay, Florence; Brioudes, Florian; Novaković, Lazar; et al. (2025)
The Plant Journal
Some silencing small (s)RNAs, comprising micro (mi)RNAs and small-interfering (si)RNAs, move between plant cells to orchestrate gene expression and defense. Besides possible redundancy or embryo lethality, a prevalent challenge in genetic studies of mobile silencing is to discriminate bona fide alterations to sRNA movement from impaired cell-autonomous sRNA activity within silencing-recipient cells. Without such clarifications, cell-to-cell mobility factors are yet to be unequivocally identified. Consequently, known properties of sRNA movement, including contextuality and directionality, remain poorly explained. Circumstantial evidence and synthetic biology pinpoint plasmodesmata (PDs) – the pores traversing plant cell walls (CWs) – as the likely channels involved. Yet, how plants control the number of primary and secondary PDs developing respectively before and after CW formation remains largely unknown. Here, we address these intertwined issues in Arabidopsis using a forward screen for compromised epidermis-to-mesophyll movement of an artificial (a)miRNA. We identify a pectin acetyl-transferase mutation that, we demonstrate, reduces amiRNA physical trafficking but also impedes siRNA, GFP, and viral movement by decreasing the frequency of leaf secondary PDs. sRNA movement at leaf interfaces involving primary PDs remains unaffected, however, as does miRNA and GFP cell-to-cell mobility in roots, hinting at how movement's contextuality and directionality might be achieved. We also show that reducing de-esterified pectin depolymerization decreases leaves' symplasmic connectivity, whereas defective pectin biogenesis increases PD number. Combining genetics with antibody-based pectin probing and atomic force microscopy helps delineate a mechanistically coherent framework whereby pectin esterification and/or abundance impact CW loosening, a process required for CW extension during which secondary PDs form to enable macromolecular trafficking.
HASTY, the Arabidopsis EXPORTIN5 ortholog, regulates cell-to-cell and vascular microRNA movement
Brioudes, Florian; Jay, Florence; Sarazin, Alexis; et al. (2021)
The EMBO Journal
Plant microRNAs (miRNAs) guide cytosolic post-transcriptional gene silencing of sequence-complementary transcripts within the producing cells, as well as in distant cells and tissues. Here, we used an artificial miRNA-based system (amiRSUL) in Arabidopsis thaliana to explore the still elusive mechanisms of inter-cellular miRNA movement via forward genetics. This screen identified many mutant alleles of HASTY (HST), the ortholog of mammalian EXPORTIN5 (XPO5) with a recently reported role in miRNA biogenesis in Arabidopsis. In both epidermis-peeling and grafting assays, amiRSUL levels were reduced much more substantially in miRNA-recipient tissues than in silencing-emitting tissues. We ascribe this effect to HST controlling cell-to-cell and phloem-mediated movement of the processed amiRSUL, in addition to regulating its biogenesis. While HST is not required for the movement of free GFP or siRNAs, its cell-autonomous expression in amiRSUL-emitting tissues suffices to restore amiRSUL movement independently of its nucleo-cytosolic shuttling activity. By contrast, HST is dispensable for the movement and activity of amiRSUL within recipient tissues. Finally, HST enables movement of endogenous miRNAs that display mostly unaltered steady-state levels in hst mutant tissues. We discuss a role for HST as a hitherto unrecognized regulator of miRNA movement in relation to its recently assigned nuclear function at the nexus of MIRNA transcription and miRNA processing.
Corrigendum: Selective autophagy degrades DICER and AGO2 and regulates miRNA activity
Gibbings, Derrick; Mostowy, Serge; Jay, Florence; et al. (2015)
Nature Cell Biology
Selective autophagy degrades DICER and AGO2 and regulates miRNA activity
Gibbings, Derrick; Mostowy, Serge; Jay, Florence; et al. (2012)
Nature Cell Biology
MicroRNAs (miRNAs) form a class of short RNAs (∼ 21 nucleotides) that post-transcriptionally regulate partially complementary messenger RNAs. Each miRNA may target tens to hundreds of transcripts to control key biological processes. Although the biochemical reactions underpinning miRNA biogenesis and activity are relatively well defined1,2 and the importance of their homeostasis is increasingly evident, the processes underlying regulation of the miRNA pathway in vivo are still largely elusive3. Autophagy, a degradative process in which cytoplasmic material is targeted into double-membrane vacuoles, is recognized to critically contribute to cellular homeostasis. Here, we show that the miRNA-processing enzyme, DICER (also known as DICER1), and the main miRNA effector, AGO2 (also known as eukaryotic translation initiation factor 2C, 2 (EIF2C2)), are targeted for degradation as miRNA-free entities by the selective autophagy receptor NDP52 (also known as calcium binding and coiled-coil domain 2 (CALCOCO2)). Autophagy establishes a checkpoint required for continued loading of miRNA into AGO2; accordingly, NDP52 and autophagy are required for homeostasis and activity of the tested miRNAs. Autophagy also engages post-transcriptional regulation of the DICER mRNA, underscoring the importance of fine-tuned regulation of the miRNA pathway. These findings have implications for human diseases linked to misregulated autophagy, DICER- and miRNA-levels, including cancer.
Suppression of both intra- and intercellular RNA silencing by the tombusviral P19 protein requires its small RNA binding property
Brioudes, Florian; Jay, Florence; Voinnet, Olivier (2022)
New Phytologist
A comment on Garnelo Gomez et al. (2021) 'The viral silencing suppressor P19 interacts with the receptorlike kinases BAM1 and BAM2 and suppresses the cell to-cell movement of RNA silencing independently of its ability to bind sRNA'
An RNA tool kit to study the status of mouse ES cells
Jay, Florence; Ciaudo, Constance (2013)
Methods
Antiviral RNA Interference in Mammalian Cells
Maillard, P.V.; Ciaudo, Constance; Marchais, Antonin; et al. (2013)
Science

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