Accelerated evolution at chaperone promoters among Antarctic notothenioid fishes.

• Published in: BMC Evolutionary Biology
• Main Authors: Bogan, Samuel N, Place, Sean P
• Format: Article in Journal/Newspaper
• Language: English
• Published: BioMed Central 2019
• Subjects: Comparative genomics; Environmental adaptation; Gene regulation; Heat shock proteins; Notothen; Promoters; cis-regulation; Antarctic; Antarc*
• Online Access: https://doi.org/10.1186/s12862-019-1524-y; https://pubmed.ncbi.nlm.nih.gov/31694524; https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6836667/

Antarctic fishes of the Notothenioidei suborder constitutively upregulate multiple inducible chaperones, a highly derived adaptation that preserves proteostasis in extreme cold, and represent a system for studying the evolution of gene frontloading. We screened for Hsf1-binding sites, as Hsf1 is a master transcription factor of the heat shock response, and highly-conserved non-coding elements within proximal promoters of chaperone genes across 10 Antarctic notothens, 2 subpolar notothens, and 17 perciform fishes. We employed phylogenetic models of molecular evolution to determine whether (i) changes in motifs associated with Hsf1-binding and/or (ii) relaxed purifying selection or exaptation at ancestral cis-regulatory elements coincided with the evolution of chaperone frontloading in Antarctic notothens.