Biology subjects

Debes, P.

Publications and source records attributed to Debes, P..

3 recordsLinked to original sources

bioRxiv2024

Sex-, development-, and nutrition-dependent expression of a major age-at-maturity gene in Atlantic salmon

Sexual maturation is a key process in the life history of an organism and is influenced by both genetic and environmental factors. In Atlantic salmon (Salmo salar), alternative alleles at the gene vgll3 have been found to associate with a large proportion of the variation in maturation age, yet the molecular and physiological mechanisms of this association are still largely unknown. Here, we investigated the mechanisms by which genetic variation in this major age-at-maturity gene translated into phenotypic variation. We established a time series of gonadal vgll3 mRNA expression in male and female Atlantic salmon in a common garden setting, starting at the prepubertal stage and spanning multiple spawning seasons. We found that vgll3 mRNA expression is reduced in early-maturing males and females. However, for the second spawning season, vgll3 expression increased with gonadal development in males, but eventually decreased in females. Expression of vgll3 had context-dependent correlations with expression of amh and lhr. We also found signs of reduced testicular vgll3 expression in a low-fat feed treatment. By significantly widening the scope of our knowledge on temporal vgll3 expression dynamics, our results exemplify that major-effect genes may use different pathways in sexes but achieve similar outcomes.

genetics↗

bioRxiv2023

Seasonal and genetic effects on lipid profiles of juvenile Atlantic salmon

Seasonality can influence many physiological traits requiring optimal energetic capacity for life-history stage transitions. In Atlantic salmon, high-energy status is essential for the initiation of maturation. Atlantic salmon lipid reserves are predominantly found in the viscera and myosepta in the muscle while the liver is essential for maintaining lipid metabolism. A genomic study found a region including a transcription co-factor-coding gene, vgll3, linked to Atlantic salmon maturation timing, which acts as an inhibitor of adipogenesis in mice, and mediates maturation via condition factor in Atlantic salmon. Here we investigate the influence of season and vgll3 genotypes associating with early (EE) and late (LL) maturation on lipid profiles in the muscle and liver in juvenile Atlantic salmon. We reared Atlantic salmon for two years until the occurrence of sexually mature males and sampled muscle and liver at two time points: spring and autumn of the second year. We found no seasonal or genotype effect in lipid profiles in muscle of immature males and females. However, in the liver we did detect a triacylglycerol (TG) enrichment and a genotype specific direction of change in membrane lipids, phosphatidylcholine (PC) and phosphatidylethanolamine (PE), from spring to autumn. Specifically, from spring to autumn membrane lipid concentrations increased in vgll3*EE individuals and decreased in vgll3*LL individuals. This could be explained with two possible scenarios 1) a seasonally more stable capacity of endoplasmic reticulum (ER) functions in vgll3*EE individuals compared to vgll3*LL individuals or 2) vgll3*LL individuals storing larger lipid droplets from spring to autumn in the liver compared to vgll3*EE individuals at the expense of ER capacity. This genotype specific seasonal direction of change in membrane lipid concentrations provides more indirect evidence that a mechanism linking vgll3 with lipid metabolism and storage exists. HighlightsO_LISeasonal lipid species profile separation in muscle and liver in juvenile Atlantic salmon C_LIO_LIGenotype specific direction of change of membrane lipids from spring to autumn C_LIO_LIIndirect evidence that a mechanism linking vgll3 with lipid metabolism and storage exists C_LI

evolutionary biology↗

bioRxiv2019

Transcription profiles of age-at-maturity-associated genes suggest cell fate commitment regulation as a key factor in the Atlantic salmon maturation process

Despite recent taxonomic diversification in studies linking genotype with phenotype, follow-up studies aimed at understanding the molecular processes of such genotype-phenotype associations remain rare. The age at which an individual reaches sexual maturity is an important fitness trait in many wild species. However, the molecular mechanisms regulating maturation timing processes remain obscure. A recent genome-wide association study in Atlantic salmon (Salmo salar) identified large-effect age-at-maturity-associated chromosomal regions including genes vgll3, akap11 and six6, which have roles in adipogenesis, spermatogenesis and the hypothalamic-pituitary-gonadal (HPG) axis, respectively. Here, we determine expression patterns of these genes during salmon development and their potential molecular partners and pathways. Using Nanostring transcription profiling technology, we show development- and tissue-specific mRNA expression patterns for vgll3, akap11 and six6. Correlated expression levels of vgll3 and akap11, which have adjacent chromosomal location, suggests they may have shared regulation. Further, vgll3 correlating with arhgap6 and yap1, and akap11 with lats1 and yap1 suggests that Vgll3 and Akap11 take part in actin cytoskeleton regulation. Tissue-specific expression results indicate that vgll3 and akap11 paralogs have sex-dependent expression patterns in gonads. Moreover, six6 correlating with slc38a6 and rtn1, and Hippo signaling genes suggests that Six6 could have a broader role in the HPG neuroendrocrine and cell fate commitment regulation, respectively. We conclude that Vgll3, Akap11 and Six6 may influence Atlantic salmon maturation timing via affecting on adipogenesis and gametogenesis by regulating cell fate commitment and the HPG axis. These results may help to unravel general molecular mechanisms behind maturation.

genetics↗