Biology subjects

Piegu, B.

Publications and source records attributed to Piegu, B..

4 recordsLinked to original sources

bioRxiv2026

Characterization of ovine follicular fluid and granulosa cell-derived extracellular vesicles and their miRNA cargo following in vitro exposure to bisphenols A and S.

Bisphenol A (BPA) and Bisphenol S (BPS) exposure disrupt ovarian function and granulosa cell (GC) steroidogenesis. Extracellular vesicles (EVs) and their miRNA cargo, as mediators of cellular response to environmental stimuli, might be involved in fertility and folliculogenesis. This study explored modulation of microRNA expression after 48h BPA or BPS exposure (10 {micro}M) in ovine primary GC and EVs from corresponding conditioned medium (CM EVs). Small RNA sequencing of control (0h) and 48h treated GC, CM EVs as well as follicular fluid EVs allowed identification of 533 ovine miRNAs, including 129 new sequences. BPA did not alter miRNA expression in GC, while BPS decreased cellular oar-24b miR. In contrast, BPA modified expression of 4 miRNAs in CM-EVs, including 3 new sequences, and two miRNAs were modified by BPS. Both compounds reduced expression of sequence homologous to miR-1306. Further studies are required to decipher their roles in bisphenol toxicity in GC.

molecular biology↗

bioRxiv2025

Characterization of interindividual DNA methylation variability in rainbow trout (Oncorhynchus mykiss)

Interindividual epigenetic variability, particularly in DNA methylation, is now recognized as a significant contributor to phenotypic diversity in humans and mammals. These epivariable regions, which make up a small fraction of the genome, are strongly influenced by genetic factors and environmental factors, especially during early development. In this context, epigenetic variability of DNA methylation has been proposed as an adaptive force involved in various environmental responses. In fish and other vertebrates, environmental factors are known to influence the health, performance and welfare, likely through the alteration of the epigenetic landscape. However, whether interindividual epigenetic variability may contribute to the phenotypic plasticity of fishes is unknown. Here we provide a first description of the rainbow trout methylome variability using a whole-genome bisulfite sequencing approach in an isogenic line to minimize genetic variation. Variable methylation regions were identified in both liver and hypothalamus tissues of 12 replicate fishes and were found enriched at gene regulatory elements, such as promoters and first introns. Gene Ontology analysis revealed functional clusters related to cellular development, neural communication, metabolic balance, and immune response. Interestingly, some variably methylated regions are found at the same genomic loci in both tissues and showed a strong intraindividual correlation in methylation levels, suggesting establishment during early embryogenesis. Overall, our work demonstrates the existence of interindividual epigenetic variability in rainbow trout and provides valuable insights into the regulatory function of DNA methylation variation that is likely involved in developmental and physiological processes.

genomics↗

bioRxiv2021

Genes encoding teleost orthologs of human haplo-insufficient and monoallelic genes remain in duplicate more frequently than the whole genome

Gene dosage is important is an important issue both in cell and evolutionary biology. Most genes are present in two copies in eukaryotic cells. The first outstanding exception is monoallelic gene expression (MA) that concerns genes localized on the X chromosome or in regions undergoing parental imprinting in eutherians, and many other genes scattered throughout the genome. The second exception concerns haploinsufficiency (HI), responsible for the fact that a single functional copy of a gene in a diploid organism is insufficient to ensure a normal biological function. One of the most important mechanisms ensuring functional innovation during evolution is Whole genome duplication (WGD). In addition to the two WGDs that have occurred in vertebrate genomes, the teleost genomes underwent an additional WGD, after their divergence from tetrapod. In the present work, we have studied on 57 teleost species whether the orthologs of human MA or HI genes remain more frequently in duplicates or returned more frequently in singleton than the rest of the genome. Our results show that the teleost orthologs of HI human genes remained more frequently in duplicate than the rest of the genome in all the teleost species studied. No signal was observed for the orthologs of genes localized on the human X chromosome or subjected to parental imprinting. Surprisingly, the teleost orthologs of the other human MA genes remained in duplicate more frequently than the rest of the genome for most teleost species. These results suggest that the teleost orthologs of MA and HI human genes also undergo selective pressures either related to absolute protein amounts and/or of dosage balance issues. However, these constraints seem to be different for MA genes in teleost in comparison with human genomes.

evolutionary biology↗

bioRxiv2017

First landscape of binding to chromosomes for a domesticated mariner transposase in the human genome: diversity of genomic targets of SETMAR isoforms in two colorectal cell lines

Setmar is a 3-exons gene coding a SET domain fused to a Hsmar1 transposase. Its different transcripts theoretically encode 8 isoforms with SET moieties differently spliced. In vitro, the largest isoform binds specifically to Hsmar1 DNA ends and with no specificity to DNA when it is associated with hPso4. In colon cell lines, we found they bind specifically to two chromosomal targets depending probably on the isoform, Hsmar1 ends and sites with no conserved motifs. We also discovered that the isoforms profile was different between cell lines and patient tissues, suggesting the isoforms encoded by this gene in healthy cells and their functions are currently not investigated.

genomics↗