Biology subjects

Gayral, M.

Publications and source records attributed to Gayral, M..

6 recordsLinked to original sources

bioRxiv2025

The unfolded protein response in grapevine: abiotic and biotic stresses induce the expression of VvbZIP60, VvbZIP17, VvBIP3, and VvIRE1

A wide range of stresses can lead to the accumulation of unfolded or misfolded proteins in the lumen of the endoplasmic reticulum (ER), a condition known as ER stress. To restore proteostasis, eukaryotic cells activate a signaling network called the unfolded protein response (UPR). In Vitis vinifera, two arms of the UPR have been identified: the IRE1/bZIP60 arm and the bZIP17 arm. Notably, no putative ortholog of bZIP28 has been found in V. vinifera, whereas this is the case for Brassicaceae species. We demonstrated that VvbZIP60 undergoes unconventional splicing upon treatment with dithiothreitol (DTT) and tunicamycin (TM), both classical ER stress inducers. Moreover, after testing several abiotic factors, we observed a strong transcriptional activation of UPR-related genes in response to heat and osmotic stresses, as well as copper exposure. Grapevine is also subject to a broad range of microbial challenges, including pathogens such as Plasmopara viticola and Botrytis cinerea. Both pathogens triggered UPR genes activation in grapevine leaves and berries. Interestingly, VvbZIP17 was also upregulated in green berries, a developmental stage associated with strong basal resistance to B. cinerea. Collectively, these findings suggest that the IRE1/bZIP60 and bZIP17 arms of the UPR are not only structurally conserved in grapevine but are also transcriptionally responsive to a variety of abiotic and biotic stresses. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=144 SRC="FIGDIR/small/669611v2_ufig1.gif" ALT="Figure 1"> View larger version (63K): org.highwire.dtl.DTLVardef@13e0b15org.highwire.dtl.DTLVardef@49967dorg.highwire.dtl.DTLVardef@1371bfborg.highwire.dtl.DTLVardef@10e09b2_HPS_FORMAT_FIGEXP M_FIG C_FIG

plant biology↗

bioRxiv2022

Cytidine deaminase regulates mitochondrial biogenesis in pancreatic cancer cells

Despite tremendous efforts from the scientific community, pancreatic ductal adenocarcinoma (PDAC) is still a deadly disease and will soon become the second cause of death by cancer worldwide1. When surgery is not possible, therapeutic options are few and ineffective2. Patients are most often treated with Folfirinox or gemcitabine chemotherapy, that extends survival in weeks to months. Cytidine deaminase (CDA) catalyzes the irreversible hydrolytic deamination of cytidine and deoxycytidine to uridine and deoxyuridine to fuel RNA and DNA synthesis3. CDA also deaminates and neutralizes deoxycytidine-based therapies, and as such, has been identified as a major contributor of tumor chemoresistance, especially to gemcitabine in PDAC3. We previously identified that CDA is elevated in PDAC tumors at diagnosis and that CDA exerts an unexpected role on DNA replication that can be exploited for therapeutic intervention4. Very recently, CDA was associated with cellular metabolism5. Here, we show that CDA promotes mitochondrial biogenesis and oxidative phosphorylation independently of its deaminase activity. This uncloaks novel therapeutic vulnerabilities in primary cancer cells that overexpress this protein. This study shines a new light on the tumoral potential of CDA in PDAC.

cancer biology↗

bioRxiv2021

Cytidine deaminase protects pancreatic cancer cells from replicative stress and drives resistance to DNA-targeting drugs

Chronic DNA replication stress and genome instability are two hallmarks of cancer that fuel oncogenesis and tumor diversity. Therapeutic approaches aimed to leverage tumor-specific replication stress to intolerable levels or to expose vulnerabilities for synthetic lethality purposes have recently gained momentum, especially for pancreatic cancer, a disease with no cure. However, the current knowledge regarding the molecular mechanisms involved in the replication stress response in pancreatic tumors is limited. Cytidine deaminase (CDA) is involved in the pyrimidine salvage pathway for DNA and RNA synthesis. Loss of CDA induces genomic instability in Bloom Syndrome, and CDA protects tumor cells from chemotherapy with pyrimidine analogs. Here, we show that CDA is overexpressed in genetically unstable pancreatic tumors, associates with a DNA replication signature, and is instrumental for experimental tumor growth. In cancer cells, CDA promotes DNA replication, increases replication fork speed, and controls replication stress and genomic stability levels. CDA expression is predictive of DNA-damaging drug efficacy and targeting CDA relieves resistance to chemotherapy in patients models, both in vitro and in vivo. Our findings shed new light on the mechanisms by which pancreatic cancer cells control replication stress, and highlight targeting of CDA as a potential therapeutic strategy to defeat tumor resistance to treatment.

cancer biology↗

bioRxiv2020

Genome-wide identification and characterization of Solanum tuberosum BiP genes reveals the role of the promoter architecture in BiP gene diversity

The endoplasmic reticulum (ER) immunoglobulin binding proteins (BiPs) are molecular chaperones involved in normal protein maturation and refolding malformed proteins through the unfolded protein response (UPR). Plants BiPs belong to a multi-gene family contributing to development, immunity, and responses to environmental stresses. This study identified three BiP homologues in the Solanum tuberosum (potato) genome using phylogenetic, amino acid sequence, 3-D protein modeling and gene structure analysis. These analyses revealed that StBiP1 and StBiP2 grouped with AtBiP2, whereas StBiP3 grouped with AtBiP3. While the protein sequences and folding structures are highly similar, these StBiPs are distinguishable by their expression patterns in different tissues and in response to environmental stressors such as treatment with heat, chemicals, or virus elicitors of UPR. Ab initio promoter analysis revealed that potato and Arabidopsis BiP1 and BiP2 promoters were highly enriched with cis regulatory elements (CREs) linked to developmental processes, whereas BiP3 promoters were enriched with stress-related CREs. The frequency and linear distribution of these CREs produced two phylogenetic branches that further resolve the groups identified through gene phylogeny and exon/intron phase analysis. These data reveal that the CRE architecture of BiP promoters potentially define their spatio -temporal expression patterns under developmental and stress related cues.

plant biology↗

bioRxiv2019

Multiple ER-to-nucleus stress signaling pathways become active during Plantago asiatica mosaic virus and Turnip mosaic virus infection in Arabidopsis thaliana.

Endoplasmic reticulum (ER) stress due to biotic or abiotic stress activates the unfolded protein response (UPR) to restore ER homeostasis. The UPR relies on multiple ER-to-nucleus signaling factors which mainly induce the expression of cytoprotective ER-chaperones. The inositol requiring enzyme (IRE1) along with its splicing target, bZIP60, restrict potyvirus, and potexvirus accumulation. Until now, the involvement of the alternative UPR pathways and the role of UPR to limit virus accumulation have remained elusive. Here, we used the Plantago asiatica mosaic virus (PlAMV) and the Turnip mosaic virus (TuMV) to demonstrate that the potexvirus triple gene block 3 (TGB3) protein and the potyvirus 6K2 protein activate the bZIP17, bZIP28, bZIP60, BAG7, NAC089 and NAC103 signaling in Arabidopsis thaliana. Using the corresponding knock-out mutant lines, we demonstrated that these factors differentially restrict local and systemic virus accumulation. We show that bZIP17, bZIP60, BAG7, and NAC089 are factors in PlAMV infection, whereas bZIP28 and bZIP60 are factors in TuMV infection. TGB3 and 6K2 transient expression in leave reveal that these alternative pathways induce BiPs expression. Finally, using dithiothreitol (DTT) and tauroursodeoxycholic acid (TUDCA) treatment, we demonstrated that the protein folding capacity significantly influences PlAMV accumulation. Together, these results indicate that multiple ER-to-nucleus signaling pathways are activated during virus infection and restrict virus accumulation through increasing protein folding capacity.\n\nSignificance statementThe IRE1/bZIP60 pathway of unfolded protein response (UPR) is activated by potyviruses and potexviruses, limiting their infection, but the role of alternative UPR pathways is unknown. This study reveals the activation of multiple ER-to-nucleus signaling pathways by the Plantago asiatica mosaic virus and the Turnip mosaic virus. We identify additional signaling pathways serve to restrict virus accumulation through increased protein folding capacity.

plant biology↗

bioRxiv2019

Infectious DNA clone technology and inoculation strategy for Rose Rosette Virus that includes all seven segments of the negative-strand RNA genome

Rose rosette virus (RRV) is an Emaravirus, a negative-sense RNA virus with a 7-segmented genome that is enclosed by a double membrane. While the genome sequences of many emaraviruses are reported, there is negligible information concerning virus replication and movement in host plants. Computational methods determined that RNA1 encoded the RNA dependent RNA polymerase (RdRp), RNA2 encoded glycoprotein precursor, and the RNA3 encoded the nucleocapsid (N), all share significant homologies with similar proteins of the Orthobunyavirus family. The RRV terminal UTR sequences are complementary and share significant identity with the UTR sequences of Bunyamwera virus. We report a minireplicon system and a full length infectious clone of RRV, which are the first for any emaravirus species. The photoreversible fluorescent iLOV protein was used to replace the RNA5 open reading frame (R5-iLOV). We demonstrate that agro-infiltration of Nicotiana benthamiana leaves to deliver RNA1, RNA3, and R5-iLOV cDNAs led to iLOV expression. A mutation was introduced into the RdRp active site and iLOV expression was eliminated. Delivery of four segments or seven segments of the RRV infectious clone produced systemic infection in N. benthamiana and rose plants. iLOV was also fused to the glycoprotein precursor (R2-iLOV). Using confocal microscopy, the R2-iLOV was seen in spherical bodies along membrane strands inside N. benthamiana epidermal cells. This new technology will enable future research to functionally characterize the RRV proteins, to study the virus-host interactions governing local and systemic infection, and examine the subcellular functions of the Gc. IMPORTANCERRV has emerged as a severe threat to cultivated roses, causing millions of dollars in losses to commercial producers. The majority of the viral gene products have not been researched or characterized until now. We constructed a minireplicon system and an infectious clone of the seven-segmented RRV genome that is contained in a binary vector and delivered by Agrobacterium. This technology has been slow to develop for viruses with negative-strand RNA genomes. It has been especially tricky for plant viruses with multicomponent negative-strand RNA genomes. We report the first reverse genetic system for a member of the genus Emaravirus, Rose rosette virus (RRV). We introduced the iLOV fluorescent protein as a fusion to the Gc protein and as a replacement for the open reading frame in genome segment 5. This game-changing reverse genetic system creates new opportunities for studying negative-strand RNA viruses in plants.

microbiology↗