Biology subjects

Galais, M.

Publications and source records attributed to Galais, M..

5 recordsLinked to original sources

bioRxiv2026

Identification of a key residue in the cellular transcription factor BCL11b important for its global acetylation and its nuclear localization

AO_SCPLOWBSTRACTC_SCPLOWThe cellular transcription factor BCL11b (B-cell CLL/lymphoma 11b) interacts with numerous cellular and viral factors to modulate gene expression positively or negatively. Post-translational modifications of BCL11b, such as SUMOylation and phosphorylation, have been documented to switch its transcriptional activity from a repressor to an activator state. In the present study, we investigated the acetylation of BCL11b and we identified the histone acetyltransferase p300 as able to acetylate BCL11b. Subsequently, we observed that the mutation of the lysine K686 residue of BCL11b (BCL11b K686R) influenced its global acetylation. Furthermore, the BCL11b K686R mutation also modulated the transcriptional regulation of BCL11b, including its activity in regulating the p21 and IL-2 promoters. This effect on transcriptional regulation was due to the importance of the lysine K686 residue for BCL11b nuclear localization. Our results underscore the critical role of the lysine K686 residue in BCL11b for its interaction with p300 and its nuclear localization, suggesting a possible function of p300 in the nuclear transport of BCL11b. Collectively, our findings contribute to a better understanding of BCL11b-mediated gene expression and of the interactions of BCL11b with cellular partners.

molecular biology↗

bioRxiv2025

Highly potent antiviral drug candidates targeting SARS-CoV-2 nsp3 and nsp5

Faced with the emergence of three epidemics linked to a virus from the coronaviridae family over the last 20 years (SARS-CoV in China in 2002, MERS-CoV in Arabia in 2012, and SARS- CoV-2 worldwide in 2019), the identification of new antiviral treatments is of major public health concern. As part of the development of new drugs, several molecular modeling tools such as docking, virtual screening and molecular dynamics were combined with databases to decipher potential inhibitors of coronavirus targets. We performed a structure-based design of antiviral drugs targeting SARS-CoV-2 non-structural proteins 3 and 5 (nsp3 and nsp5) based on a high-throughput virtual screening of the ZINC15 database tranches for ligand docking followed by click chemistry with a particular attention paid to relaxed structures mimicking potential in vivo interactions. Based on the above in silico approaches, we selected two small molecules with high affinity binding for nsp3 and nsp5 named Amb929 and Amb701, respectively. We then assessed the antiviral activity of both the Amb929 and Amb701 against SARS-CoV-2 infection taking into account their potential cytotoxicity. Although both compounds inhibited SARS-CoV-2 replication in vitro, Amb929 displayed the most efficient anti-SARS-CoV-2 activity. Among these two drugs, Amb929 was less cytotoxic compared to Amb701, demonstrating an optimal anti-SARS-CoV-2 response with a high selectivity index in cell culture and a high inhibition of SARS-CoV-2 replication compared to untreated condition on a model of human airway epithelium (HAE), paving the way for the development of drugs with very potent anti-coronavirus activity.

microbiology↗

bioRxiv2024

Unbiased and comprehensive identification of viral encoded circular RNAs in a large range of viral species and families

Non-coding RNAs play a significant role in viral infection cycles, with recent attention focused on circular RNAs (circRNAs) originating from various viral families. Notably, these circRNAs have been associated with oncogenesis and alterations in viral fitness. However, identifying their expression has proven more challenging than initially anticipated due to unique viral characteristics. This challenge has the potential to impede progress in our understanding of viral circRNAs. Key hurdles in working with viral genomes include: (1) the presence of repetitive regions that can lead to misalignment of sequencing reads, and (2) unconventional splicing mechanisms that deviate from conserved eukaryotic patterns. To address these challenges, we developed vCircTrappist, a bioinformatic pipeline tailored to identify backsplicing events and pinpoint loci expressing circRNAs in RNA sequencing data. Applying this pipeline, we obtained novel insights from both new and existing datasets encompassing a range of animal and human pathogens belonging to Herpesviridae, Retroviridae, Adenoviridae and Orthomyxoviridae families. Subsequent RT-PCR and Sanger sequencings validated the accuracy of the developed bioinformatic tool for a selection of new candidate viral encoded circRNAs. These findings demonstrate that vCircTrappist is an open and unbiased approach for comprehensive identification of virus-derived circRNAs. Significance StatementCircular RNAs (circRNAs) were revealed to have prominent roles in cellular life in the past decade. They were more recently shown to be expressed by viruses, influencing their infectious cycles and host-pathogen relationship. In this context, viruses that were not previously associated with cellular splicing processes are shown to express circRNAs through unknown mechanisms. These non-canonical circRNAs were already shown to be important in the viral cycle and pathogenesis of the viruses they are encoded from. Here, we propose a bioinformatics pipeline that bypasses the limitations of the existing tools in the identification of viral circRNA. Using this pipeline, we discovered numerous candidates and invite the reader to start its own exploration in the realm of viral encoded circRNAs. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=72 SRC="FIGDIR/small/600382v1_ufig1.gif" ALT="Figure 1"> View larger version (16K): org.highwire.dtl.DTLVardef@1003330org.highwire.dtl.DTLVardef@20d366org.highwire.dtl.DTLVardef@116f38forg.highwire.dtl.DTLVardef@1d04a76_HPS_FORMAT_FIGEXP M_FIG C_FIG

bioinformatics↗

bioRxiv2021

Implication of the cellular factor CTCF in the regulation of Bovine Leukemia Virus latency and tridimensional chromatin organization

Bovine Leukemia Virus (BLV)-induced tumoral development is a multifactorial phenomenon which remains largely unelucidated. Here, we highlighted the critical role of the cellular CCCTC-binding factor (CTCF) both in the regulation of BLV transcriptional activities and in the deregulation of the tridimensional (3D) chromatin architecture surrounding the BLV integration site. We demonstrated the in vivo recruitment of CTCF to three conserved CTCF binding motifs along the BLV provirus. Next, we showed a critical role for CTCF in delimitating the epigenetic landscape along the BLV provirus as well as to repress the 5Long Terminal Repeat (LTR) promoter activity, thereby contributing to viral latency, while favoring the 3LTR promoter activity. Finally, we demonstrated that BLV integration deregulated host cellular 3D chromatin organization through the formation of abnormal viral/host chromatin loops. Altogether, our results highlight CTCF as a new critical effector of BLV transcriptional regulation and BLV-induced physiopathology.

molecular biology↗

bioRxiv2019

HIV-1 Env induces pexophagy and an oxidative stress leading to uninfected CD4+ T cell death

The immunodeficiency observed in HIV-1-infected patients is mainly due to uninfected bystander CD4+ T lymphocytes death. The viral envelope glycoproteins (Env), expressed at the surface of infected cells, play a key role in this process. Env triggers autophagy, process necessary to subsequent apoptosis, and to production of Reactive Oxygen Species (ROS) in bystander CD4+ T cells. Here, we demonstrate that Env-induced oxidative stress is responsible for their death by apoptosis. Moreover, we report that peroxisomes, organelles involved in the control of oxidative stress, are targeted by Env-mediated autophagy. Indeed, we observe a selective autophagy-dependent decrease in the expression of peroxisomal proteins, catalase and PEX14, upon Env exposure, since the down-regulation of either BECLIN 1 or p62/SQSTM1 restores their expression levels. Fluorescence studies allowed us to conclude that Env-mediated autophagy degrades these entire organelles and specifically the mature ones. Together, our results on Env-induced pexophagy provide new clues on HIV-1-induced immunodeficiency.

cell biology↗