Evolutionary Plasticity in Detoxification Gene Modules: The Preservation and Loss of the Pregnane X Receptor in Chondrichthyes Lineages.
Elza S S Fonseca, Raquel Ruivo, André M Machado, Francisca Conrado, Boon-Hui Tay, Byrappa Venkatesh, Miguel M Santos, L Filipe C Castro
Author Information
Elza S S Fonseca: CIIMAR/CIMAR-Interdisciplinary Centre of Marine and Environmental Research, 4450-208 Matosinhos, Portugal. fonseca.ess@gmail.com.
Raquel Ruivo: CIIMAR/CIMAR-Interdisciplinary Centre of Marine and Environmental Research, 4450-208 Matosinhos, Portugal. ruivo.raquel@gmail.com. ORCID
André M Machado: CIIMAR/CIMAR-Interdisciplinary Centre of Marine and Environmental Research, 4450-208 Matosinhos, Portugal. andre.machado@ciimar.up.pt. ORCID
Francisca Conrado: CIIMAR/CIMAR-Interdisciplinary Centre of Marine and Environmental Research, 4450-208 Matosinhos, Portugal. fi.silva@campus.fct.unl.pt.
Boon-Hui Tay: Comparative Genomics Laboratory, Institute of Molecular and Cell Biology, A*STAR (Agency for Science, Technology and Research), Biopolis, Singapore 138673, Singapore. mcblab46@imcb.a-star.edu.sg.
Byrappa Venkatesh: Comparative Genomics Laboratory, Institute of Molecular and Cell Biology, A*STAR (Agency for Science, Technology and Research), Biopolis, Singapore 138673, Singapore. mcbbv@imcb.a-star.edu.sg.
Miguel M Santos: CIIMAR/CIMAR-Interdisciplinary Centre of Marine and Environmental Research, 4450-208 Matosinhos, Portugal. santosmafm@gmail.com.
L Filipe C Castro: CIIMAR/CIMAR-Interdisciplinary Centre of Marine and Environmental Research, 4450-208 Matosinhos, Portugal. filipe.castro@ciimar.up.pt.
To appraise how evolutionary processes, such as gene duplication and loss, influence an organism's xenobiotic sensitivity is a critical question in toxicology. Of particular importance are gene families involved in the mediation of detoxification responses, such as members of the nuclear receptor subfamily 1 group I (NR1I), the pregnane X receptor (), and the constitutive androstane receptor (). While documented in multiple vertebrate genomes, and display an intriguing gene distribution. is absent in birds and reptiles, while shows a tetrapod-specific occurrence. More elusive is the presence of and gene orthologs in early branching and ecologically-important Chondrichthyes (chimaeras, sharks and rays). Therefore, we investigated various genome projects and use them to provide the first identification and functional characterization of a Chondrichthyan PXR from the chimaera elephant shark (, Holocephali). Additionally, we substantiate the targeted gene loss in Elasmobranchii (sharks and rays). Compared to other vertebrate groups, the chimaera ortholog displays a diverse expression pattern (skin and gills) and a unique activation profile by classical xenobiotic ligands. Our findings provide insights into the molecular landscape of detoxification mechanisms and suggest lineage-specific adaptations in response to xenobiotics in gnathostome evolution.