Biology subjects

Chauve, L.

Publications and source records attributed to Chauve, L..

3 recordsLinked to original sources

bioRxiv2023

Synthetic autotetraploid Caenorhabditis elegans resist severe cold stress by escaping cold induced death at the gravid adult stage.

Whole genome duplication (WGD) is a well-studied yet enigmatic phenomenon. While it has long been recognised as contributing numerous genes to many eukaryotic lineages and often implicated in evolutionary radiations, how these lineages overcome the known burdens of polyploidy is poorly understood. Circumstantial evidence of many WGD events coinciding with periods of otherwise mass extinction is consistent with the hypothesis that polyploidy is conditionally advantageous under stress conditions. While support for this comes from both theoretical work and field studies, direct evidence is lacking, especially in animals. Here we compare diploid and neo-tetraploid Caenorhabditis elegans and show that tetraploid animals exhibit increased resilience under specific stress conditions related to temperature changes. Most notably, under severe cold stress gravid neo-tetraploids massively escape cold-induced death, and generate more progeny, of similar quality, than diploid animals. This is the first demonstration of the effects of polyploidy on stress resistance and physiology in animals.

cell biology↗

bioRxiv2023

Inter individual variability in neuronal expression of heat shock protein genes predicts stress survival in Caenorhabditis elegans.

Despite being isogenic and grown under controlled conditions, C. elegans populations exhibit widespread inter-individual variability in many traits, making it an ideal model organism to investigate non-genetic influences on phenotypic diversity. Our particular interest is to study the consequences of inter-individual variability in genes encoding heat shock proteins, which are expressed at low levels under non-stimulated conditions. To robustly quantify inter-individual gene expression, we developed a novel pipeline that combines a highly efficient cDNA extraction method with a high-throughput qPCR nanofluidics technology with a bespoke computational analysis. We validated our approach by benchmarking against in vivo reporters. We also screened among hundreds of stress inducible genes, and identified a regulon formed by transcripts belonging to the inducible heat shock protein family. We demonstrate, using a bipartite in vivo fluorescent reporter, that the inter-individual variability in the stress regulon stems mostly from anterior neurons. Our studies demonstrate for the first time that, under physiological and unstimulated conditions, the variable expression of neural stress responses has cross-tissue consequences for fitness at the individual worm level, suggesting an adaptive role under variable environmental conditions.

molecular biology↗

bioRxiv2019

A neuronal thermostat controls membrane fluidity in C. elegans

An organisms ability to adapt to heat can be key to its survival. Cells adapt to temperature shifts by adjusting lipid desaturation levels and the fluidity of membranes in a process that is thought to be controlled cell autonomously. We have discovered that subtle, step-wise increments in ambient temperature can lead to the conserved heat shock response being activated in head neurons of C. elegans. This response is exactly opposite to the expression of the lipid desaturase FAT-7 in the worms gut. We find that the over-expression of the master regulator of this response, Hsf-1, in head neurons, causes extensive fat remodeling to occur across tissues. These changes include a decrease in FAT-7 expression and a shift in the levels of unsaturated fatty acids in the plasma membrane. These shifts are in line with membrane fluidity requirements to survive in warmer temperatures. We have identified that the cGMP receptor, TAX-2/TAX-4, as well as TGF-{beta}/BMP signaling, as key players in the transmission of neuronal stress to peripheral tissues. This is the first study to suggest that a thermostat-based mechanism can centrally coordinate membrane fluidity in response to warm temperatures across tissues in multicellular animals.

genetics↗