Dataset Information

Effect of triploidy on liver gene expression in coho salmon (Oncorhynchus kisutch) under different metabolic states.

ABSTRACT: BACKGROUND:Triploid coho salmon are excellent models for studying gene dosage and the effects of increased cell volume on gene expression. Triploids have an additional haploid genome in each cell and have fewer but larger cells than diploid coho salmon to accommodate the increased genome size. Studying gene expression in triploid coho salmon provides insight into how gene expression may have been affected after the salmonid-specific genome duplication which occurred some 90 MYA. Triploid coho salmon are sterile and consequently can live longer and grow larger than diploid congeners in many semelparous species (spawning only once) because they never reach maturity and post-spawning mortality is averted. Triploid fishes are also of interest to the commercial sector (larger fish are more valuable) and to fisheries management since sterile fish can potentially minimize negative impacts of escaped fish in the wild. RESULTS:The vast majority of genes in liver tissue had similar expression levels between diploid and triploid coho salmon, indicating that the same amount of mRNA transcripts were being produced per gene copy (positive gene dosage effects) within a larger volume cell. Several genes related to nutrition and compensatory growth were differentially expressed between diploid and triploid salmon, indicating that some loci are sensitive to cell size and/or DNA content per cell. To examine how robust expression between ploidies is under different conditions, a genetic/metabolic modifier in the form of different doses of a growth hormone transgene was used to assess gene expression under conditions that the genome has not naturally experienced or adapted to. While many (up to 1400) genes were differentially expressed between non-transgenic and transgenic fish, relatively few genes were differentially expressed between diploids and triploids with similar doses of the transgene. These observations indicate that the small effect of ploidy on gene expression is robust to large changes in physiological state. CONCLUSIONS:These findings are of interest from a gene regulatory perspective, but also valuable for understanding phenotypic effects in triploids, transgenics, and triploid transgenics that could affect their utility in culture conditions and their fitness and potential consequences of release into nature.

SUBMITTER: Christensen KA

PROVIDER: S-EPMC6500012 | biostudies-literature | 2019 May

REPOSITORIES: biostudies-literature

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Effect of triploidy on liver gene expression in coho salmon (Oncorhynchus kisutch) under different metabolic states.

Christensen Kris A KA Sakhrani Dionne D Rondeau Eric B EB Richards Jeffery J Koop Ben F BF Devlin Robert H RH

BMC genomics 20190503 1

<h4>Background</h4>Triploid coho salmon are excellent models for studying gene dosage and the effects of increased cell volume on gene expression. Triploids have an additional haploid genome in each cell and have fewer but larger cells than diploid coho salmon to accommodate the increased genome size. Studying gene expression in triploid coho salmon provides insight into how gene expression may have been affected after the salmonid-specific genome duplication which occurred some 90 MYA. Triploid ...[more]

PMID: 31053056

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Project description:Wild stocks of Pacific salmon in the Northwestern United States have declined in recent years, and the major factors contributing to these losses include water pollution and loss of habitat. In salmon, sublethal chemical exposures may impact critical behaviors (such as homing, feeding, predator-avoidance) that are important for species survival. Therefore, understanding the potential for these species to biotransform organic compounds within sensitive target tissues such as liver, gills and olfactory region can help estimate or predict their susceptibility to pollutants. In this study, we used real-time quantitative polymerase chain reaction (Q-PCR), Western blotting, and catalytic assays to characterize the expression of Phase I biotransformation enzymes in coho salmon (Oncorhynchus kisutch), a sensitive species in the Pacific Northwest. Gene expression analysis using Q-PCR assays developed for coho genes revealed the presence of the predominant cytochrome P450 mRNAs (CYP1A, CYP2K1, CYP2M1, CYP3A27) in the olfactory rosettes and provided quantitative mRNA expression levels in coho liver and gills. Q-PCR analysis revealed relatively high expression of the major CYP isoforms in the liver and olfactory rosettes, which was generally confirmed by Western blotting. Extrahepatic CYP expression was generally higher in the olfactory rosettes as compared to the gills. Catalytic studies demonstrated functional CYP1A-dependent ethoxyresorufin-O-deethylase, CYP2-dependent pentoxyresorufin-O-dealkylase, CYP2K1-dependent testosterone 16beta-hydroxylase, and CYP3A27-dependent testosterone 6beta-hydroxylase activities in liver, but not at detectable levels in gills. In contrast, flavin-containing monooxygenase (FMO)-dependent thiourea S-oxidase activity was readily observed in the gills and was substantially higher than that observed in liver. Collectively, the results of this study suggest that the olfactory rosettes are important sites of extrahepatic biotransformation in coho salmon, and that tissue specific-differences in Phase I metabolism may lead to contrasting tissue-specific biotransformation capabilities in this species.

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Dataset Information

Effect of triploidy on liver gene expression in coho salmon (Oncorhynchus kisutch) under different metabolic states.

Publications

Effect of triploidy on liver gene expression in coho salmon (Oncorhynchus kisutch) under different metabolic states.

Similar Datasets

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