Expression of thermal tolerance genes in two Drosophila species with different acclimation capacities
Sørensen, Jesper Givskov (Aarhus University. Department of Bioscience, Genetics, Ecology and Evolution)
Puig Giribets, Marta (Universitat Autònoma de Barcelona. Departament de Genètica i de Microbiologia)
Tarrío, Rosa (Universitat Autònoma de Barcelona. Departament de Genètica i de Microbiologia)
Rodríguez-Trelles, Francisco (Universitat Autònoma de Barcelona. Departament de Genètica i de Microbiologia)
Schou, Mads Fristrup (Lund University. Department of Biology)
Loeschcke, Volker (Aarhus University. Department of Bioscience, Genetics, Ecology and Evolution)

Date:	2019
Abstract:	Heat tolerance increases at higher acclimation temperatures in D. melanogaster, but not in D. subobscura. The two species represent separate lineages of the subgenus Sophophora of Drosophila with contrasting tropical African and temperate Palearctic evolutionary histories. D. melanogaster has five copies of the inducible hsp70 gene distributed in two clusters, named A (with two copies) and B (three copies), while D. subobscura has only two copies arranged similarly to cluster A of D. melanogaster. The hsp70s of the two species also differ in their cis-regulatory regions, with D. melanogaster exhibiting features of a faster and more productive promoter. We predicted that the interspecific variation in acclimation capacity of heat tolerance is explained by evolved variation in expression of the major group of heat shock proteins. To test this prediction, we compared basal levels of gene expression at different developmental temperatures within each of the two species. Furthermore, we explored the heat hardening dynamics by measuring the induction of gene expression during a ramping assay. The prediction of a stronger heat shock protein response in D. melanogaster as compared to D. subobscura was confirmed for both long-term acclimation and short-term hardening. For D. melanogaster the upregulation with temperature ramping ranged from less than two fold (hsp26) to 2500 fold (hsp70A) increase. In all cases induction in D. melanogaster exceeded that of D. subobscura homologs. These differences correlate with structural differences in the regulatory regions of hsp70, and might explain differences in acclimation capacity among species. Finally, in D. melanogaster we found an indication of an inverse relationship between basal and induced levels of hsp70A and hsp83 expression, suggesting a divergent role for thermal adaptation of these genes at benign and stressful temperatures, respectively.
Grants:	Agencia Estatal de Investigación CGL2017-89160P Agència de Gestió d'Ajuts Universitaris i de Recerca 2017/SGR-1379
Rights:	Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, i la comunicació pública de l'obra, sempre que no sigui amb finalitats comercials, i sempre que es reconegui l'autoria de l'obra original. No es permet la creació d'obres derivades.
Language:	Anglès
Document:	Article ; recerca ; Versió acceptada per publicar
Subject:	Drosophila melanogaster ; Drosophila subobscura ; Gene expression ; Heat tolerance ; Hsp ; Plasticity
Published in:	Journal of Thermal Biology, Vol. 84 (August 2019) , p. 200-207, ISSN 1879-0992

DOI: 10.1016/j.jtherbio.2019.07.005
PMID: 31466754

Postprint 32 p, 702.8 KB

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