Model of gene expression in extreme cold - reference transcriptome for the high-Antarctic cryopelagic notothenioid fish Pagothenia borchgrevinki

• Published in: BMC Genomics
• Main Authors: Bilyk, Kevin T., Cheng, C. H.Christina
• Format: Text
• Language: unknown
• Published: Montclair State University Digital Commons 2013
• Subjects: Antarctic fish; Cold adaptation; Cold specialization; Heat tolerance; Notothenioidei; Transcriptome; Antarctic; Southern Ocean; Antarc*
• Online Access: https://digitalcommons.montclair.edu/biology-facpubs/482; https://doi.org/10.1186/1471-2164-14-634

Background: Among the cold-adapted Antarctic notothenioid fishes, the high-latitude bald notothen Pagothenia borchgrevinki is particularly notable as the sole cryopelagic species, exploiting the coldest and iciest waters of the Southern Ocean. Because P. borchgrevinki is a frequent model for investigating notothenioid cold-adaptation and specialization, it is imperative that " omic" tools be developed for this species. In the absence of a sequenced genome, a well annotated reference transcriptome of the bald notothen will serve as a model of gene expression in the coldest and harshest of all polar marine environments, useful for future comparative studies of cold adaptation and thermal responses in polar teleosts and ectotherms.Results: We sequenced and annotated a reference transcriptome for P. borchgrevinki, with added attention to capturing the transcriptional responses to acute and chronic heat exposures. We sequenced by Roche 454 a normalized cDNA library constructed from pooled mRNA encompassing multiple tissues taken from environmental, warm acclimating, and acute heat stressed specimens. The resulting reads were assembled into 42,620 contigs, 17,951 of which could be annotated. We utilized this annotated portion of the reference transcriptome to map short Illumina reads sequenced from the gill and liver of environmental specimens, and also compared the gene expression profiles of these two tissue transcriptomes with those from the temperate model fish Danio rerio. From this, we identified a conserved group of 58 GO terms, in which terms related to transcription and its regulation, ubiquitin-protein ligase activity, protein ubiquitination, and protein binding among others are more prevalent in the bald notothen, suggesting the pertinent genes play essential roles in cold temperature functioning.Conclusion: We sequenced multiple tissue transcriptomes from native and heat-exposed experimental specimens of the high Antarctic, cryopelagic notothenioid P. borchgrevinki to construct a reference transcriptome. ...