Biology subjects

Rialle, S.

Publications and source records attributed to Rialle, S..

6 recordsLinked to original sources

bioRxiv2025

Dorsal Striatum Parvalbumin interneurons translatome unveiled

Parvalbumin (PV) interneurons in the dorsal striatum (DS) are fast-spiking GABAergic cells critical for feedforward inhibition and synaptic integration within basal ganglia circuits. Despite their well-characterized electrophysiological roles, their molecular identity remains incompletely defined. Using the Ribotag approach in Pvalb-Cre mice, we profiled the translatome of DS PV interneurons and identified over 2,700 transcripts significantly enriched (fold-change > 1.5) in this population. Our data validate established PV markers and reveal a distinct molecular signature of DS PV neurons compared to PV interneurons from the nucleus accumbens. Gene ontology analyses highlight prominent expression of genes related to extracellular matrix components, cell adhesion molecules, synaptic organization, ion channels, and neurotransmitter receptors, particularly those mediating glutamatergic and GABAergic signaling. Notably, perineuronal net markers were robustly expressed in DS PV interneurons and confirmed by immunofluorescence. Transcriptomic analysis of DS PV neurons following repeated d-amphetamine exposure identified Gm20683 as the only differentially expressed transcript between treated groups. Furthermore, RNAseq analysis of mice subjected to an operant behavior paradigm with two types of food reward (high-palatable diet or standard chow) identified over 1,000 and 100 genes enriched in DS PV neurons from standard and high-palatable masters, respectively. These findings provide a comprehensive molecular profile of DS PV interneurons, distinguishing them from other striatal PV populations, and reveal specific gene expression changes associated with psychostimulant exposure and reward-driven behaviors. Our findings deepen insight into the molecular mechanisms of PV interneuron activity in striatal circuits and their potential roles in neuropsychiatric, motor and reward-related disorders.

neuroscience↗

bioRxiv2024

Gene coexpression network analysis of galactomannan biosynthesis and endosperm maturation in species of the genus Coffea

In a few important plant families and genera, including Arecaceae, Fabaceae and the genus Coffea, the main seed storage polysaccharide is not starch but cell wall galactomannans. Such seeds are albuminous with a persistent copious living endosperm that accumulates galactomannans. However, our understanding of the regulation of endosperm maturation, cell wall formation and galactomannan biosynthesis in albuminous seeds remains very limited. To gain insights into these processes, a large RNA-seq dataset was produced (14 coffee species x 5 endosperm developmental stages) and scrutinized using gene coexpression network analysis. The network revealed tight transcriptional coordination of the core galactomannan biosynthetic machinery for sucrose import, glycolysis, nucleotide sugar synthesis and transport, arabinogalactan protein and cellulose synthesis, and regulation of the trans-Golgi network. The orchestration of galactomannan and oil accumulation during endosperm maturation appeared to be exerted by the transcription factors FUSCA3, WRINKLED1, SHINE2 and DREB2D. The latter was the only coexpression partner of galactomannan biosynthetic genes. Numerous key genes of galactomannan biosynthesis were significantly upregulated in coffee somatic embryos overexpressing DREB2D, which showed increased production of UDP-galactose and diversion towards raffinose family oligosaccharides. Further, most genes of the galactomannan coexpression module were identified as DREB2D target genes by DAP-seq analysis. HighlightGene coexpression network analysis of the maturing endosperm identified the AP2/ERF transcription factor DREB2D as a major regulator of galactomannan accumulation in the cell walls of albuminous coffee seeds.

plant biology↗

bioRxiv2024

Co-translational sorting enables a single mRNA to generate distinct polysomes with different localizations and protein fates

{beta}-catenin is a multi-functional protein playing essential roles in tissue homeostasis and cancer. It bridges E-cadherin to the cytoskeleton and also activates transcription in response to Wnt. Plasma membrane {beta}-catenin is stable whereas without Wnt, cytoplasmic {beta}-catenin is degraded by the destruction complex, composed of APC and Axin. Here, we show that APC and Axin associate with many mRNAs and that this occurs via the nascent protein chains. Notably, APC and Axin bind {beta}-catenin mRNAs present as either single polysome or polysome condensates, and co-translational interactions constitute the major fraction of their binding to the {beta}-catenin protein. Remarkably, E-cadherin also binds {beta}-catenin co-translationally, and {beta}-catenin mRNAs localize either with APC in the cytosol or E-cadherin at the plasma membrane. Thus, co-translational interactions sort {beta}-catenin mRNAs into distinct polysome populations that spatially segregate in cells and synthesize proteins with different functions. Co-translational polysome sorting provides a mechanism to regulate the fate of multi-functional proteins.

molecular biology↗

bioRxiv2020

A genome-wide CRISPR/Cas9 knock-out screen identifies the DEAD box RNA helicase DDX42 as a broad antiviral inhibitor

Genome-wide screens are powerful approaches to unravel new regulators of viral infections. Here, we used a CRISPR/Cas9 screen to reveal new HIV-1 inhibitors. This approach led us to identify the RNA helicase DDX42 as an intrinsic antiviral inhibitor. DDX42 was previously described as a non-processive helicase, able to bind RNA secondary structures such as G-quadruplexes, with no clearly defined function ascribed. Our data show that depletion of endogenous DDX42 significantly increased HIV-1 DNA accumulation and infection in cell lines and primary cells. DDX42 overexpression inhibited HIV-1, whereas a dominant-negative mutant increased infection. Importantly, DDX42 also restricted retrotransposition of LINE-1, infection with other retroviruses and positive-strand RNA viruses, including CHIKV and SARS-CoV-2. However, DDX42 did not inhibit infection with three negative-strand RNA viruses, arguing against a general, unspecific effect on target cells, which was confirmed by RNA-seq analysis. DDX42 was found in the vicinity of viral elements by proximity ligation assays, and cross-linking RNA immunoprecipitation confirmed a specific interaction of DDX42 with RNAs from sensitive viruses. This strongly suggested a direct mode of action of DDX42 on viral ribonucleoprotein complexes. Taken together, our results show for the first time a new and important role of DDX42 in intrinsic antiviral immunity.

microbiology↗

bioRxiv2018

Differential immune gene expression associated with contemporary range expansion of two invasive rodents in Senegal

BackgroundBiological invasions are major anthropogenic changes associated with threats to biodiversity and health. What determines the successful establishment of introduced populations still remains unsolved. Here we explore the appealing assertion that invasion success relies on immune phenotypic traits that would be advantageous in recently invaded sites. ResultsWe compared gene expression profiles between anciently and recently established populations of two major invading species, the house mouse Mus musculus domesticus and the black rat Rattus rattus, in Senegal. Transcriptome analyses revealed respectively 364 and 83 differentially expressed genes along the mouse and rat invasion routes. Among them, 20.0% and 10.6% were annotated with functions related to immunity. All immune-related genes detected along the mouse invasion route were over-expressed in recently invaded sites. Genes of the complement activation pathway were over-represented. Results were less straightforward when considering the black rat as no particular immunological process was over-represented. ConclusionsWe revealed changes in transcriptome profiles along invasion routes. Patterns differed between both invasive species. These changes potentially be driven by increased infection risks in recently invaded sites for the house mouse and stochastic events associated with colonization history for the black rat. These results provide a first step in identifying the immune ecoevolutionary processes potentially involved in invasion success.

ecology↗

bioRxiv2018

Transcriptional plasticity evolution in two strains of Spodoptera frugiperda (Lepidoptera: Noctuidae) feeding on alternative host-plants

AO_SCPLOWBSTRACTC_SCPLOWSpodoptera frugiperda, the fall armyworm (FAW), is an important agricultural pest in the Americas and an emerging pest in sub-Saharan Africa, India, East-Asia and Australia, causing damage to major crops such as corn, sorghum and soybean. While FAW larvae are considered polyphagous, differences in diet preference have been described between two genetic variants: the corn strain (sf-C) and the rice strain (sf-R). These two strains are sometimes considered as distinct species, raising the hypothesis that ost plant specialization might have driven their divergence. To test this hypothesis, we irst performed controlled reciprocal transplant (RT) experiments to address the impact of plant diet on several traits linked to the fitness of the sf-C and sf-R strains. The phenotypical data suggest that sf-C is specialized to corn. We then used RNA-Se to identify constitutive transcriptional differences between strains, regardless of diet, in laboratory as well as in natural populations. We found that variations in mitochon rial transcription levels are among the most substantial and consistent differences between the two strains. Since mitochondrial genotypes also vary between the strains, we believe the mitochondria may have a significant role in driving strain divergence.

evolutionary biology↗