Molecular evolution of myoglobin in the Tibetan Plateau endemic schizothoracine fish (Cyprinidae, Teleostei) and tissue-specific expression changes under hypoxia
Myoglobin (Mb) is an oxygen-binding hemoprotein that was once thought to be exclusively expressed in oxidative myocytes of skeletal and cardiac muscle where it serves in oxygen storage and facilitates intracellular oxygen diffusion. In this study, we cloned the coding sequence of the Mb gene from four species, representing three groups, of the schizothoracine fish endemic to the Qinghai-Tibetan Plateau (QTP), then conducted molecular evolution analyses. We also investigated tissue expression patterns of Mb and the expression response to moderate and severe hypoxia at the mRNA and protein levels in a representative of the highly specialized schizothoracine fish species, Schizopygopsis pylzovi. Molecular evolution analyses showed that Mb from the highly specialized schizothoracine fish have undergone positive selection and one positively selected residue (81L) was identified, which is located in the F helix, close to or in contact with the heme. We present tentative evidence that the Mb duplication event occurred in the ancestor of the schizothoracine and Cyprininae fish (common carp and goldfish), and that the Mb2 paralog was subsequently lost in the schizothoracine fish. In S. pylzovi, Mb mRNA is expressed in various tissues with the exception of the intestine and gill, but all such tissues, including the liver, muscle, kidney, brain, eye, and skin, expressed very low levels of Mb mRNA (< 8.0%) relative to that of the heart. The trace levels of Mb expression in non-muscle tissues are perhaps the major reason why non-muscle Mb remained undiscovered for so long. The expression response of the Mb gene to hypoxia at the mRNA and protein levels was strikingly different in S. pylzovi compared to that found in the common carp, medaka, zebrafish, and goldfish, suggesting that the hypoxia response of Mb in fish may be species and tissue-specific. Notably, severe hypoxia induced significant expression of Mb at the mRNA and protein levels in the S. pylzovi heart, which suggests Mb has a major role in the supply of oxygen to the heart of Tibetan Plateau fish.
KeywordsSchizothoracine fishes Myoglobin Evolution Expression Hypoxia Qinghai-Tibetan Plateau
We would like to thank the native English speaking scientists of Elixigen Company (Huntington Beach, California) for editing our manuscript.
This work was supported by grants to D. Qi from the National Natural Science Foundation of China (31460094) and the Natural Science Foundation of Qinghai Science & Technology Department in China (2015-ZJ-901).
Compliance with ethical standards
All research involving animals in this study followed the bylaws for experiments on animals and was approved by the Animal Care and Use Committee of Qinghai University. All specimens were collected as live specimens from their habitats with the permission of the Wild Animal and Plant Protection Station of Qinghai Province and Autonomous Region, China.
- Avivi A, Gerlach F, Joel A, Reuss S, Burmester T, Nevo E, Hankeln T (2010) Neuroglobin, cytoglobin, and myoglobin contribute to hypoxia adaptation of the subterranean mole rat Spalax. Proc Natl Acad Sci USA 107(50):21570–21575. https://doi.org/10.1073/pnas.1015379107 CrossRefPubMedPubMedCentralGoogle Scholar
- Cao WX, Chen YY, Wu YF, Zhu SQ (1981) Origin and evolution of schizothoracine fishes in relation to the upheaval of the Xizang Plateau, in Collection in studies on the period, amplitude and type of the uplift of the Qinghai-Xizang Plateau in: the team of the comprehensive scientific expedition to the Qinghai-Xizang Plateau CAoS (ed) studies on the period, amplitude and type of the uplift of the Qinghai-Xizang Plateau. Science Press, Beijing, pp 118–130Google Scholar
- Chen YF, Cao WY (2000) Schizothoracinae. In: Yue PQ (ed) Fauna Sinica, Osteichthyes, Cypriniformes III. Science Press, Beijing, pp 273–390Google Scholar
- Duplicated gene evolution following whole-genome duplication in teleost fish. In Friedberg F (ed) Gene duplication. InTech, Rijeka, Croatia. https://doi.org/10.5772/22039
- Helbo S, Dewilde S, Williams DR, Berghmans H, Berenbrink M, Cossins AR, Fago A (2012) Functional differentiation of myoglobin isoforms in hypoxia-tolerant carp indicates tissue-specific protective roles. Am J Physiol Regul Integr Comp Physiol 302:R693-701. https://doi.org/10.1152/ajpregu.00501.2011
- Holland PW, Garcia-Fernandez J, Williams NA, Sidow A (1994) Gene duplications and the origins of vertebrate development. Dev Suppl 125–133. https://www.ncbi.nlm.nih.gov/pubmed/7579513
- Jaillon O, Aury JM, Brunet F, Petit JL, Stange-Thomann N, Mauceli E, Bouneau L, Fischer C, Ozouf-Costaz C, Bernot A, Nicaud S, Jaffe D, Fisher S, Lutfalla G, Dossat C, Segurens B, Dasilva C, Salanoubat M, Levy M, Boudet N, Castellano S, Anthouard V, Jubin C, Castelli V, Katinka M, Vacherie B, Biémont C, Skalli Z, Cattolico L, Poulain J, de Berardinis V, Cruaud C, Duprat S, Brottier P, Coutanceau JP, Gouzy J, Parra G, Lardier G, Chapple C, McKernan KJ, McEwan P, Bosak S, Kellis M, Volff JN, Guigó R, Zody MC, Mesirov J, Lindblad-Toh K, Birren B, Nusbaum C, Kahn D, Robinson-Rechavi M, Laudet V, Schachter V, Quétier F, Saurin W, Scarpelli C, Wincker P, Lander ES, Weissenbach J, Roest Crollius H (2004) Genome duplication in the teleost fish Tetraodon nigroviridis reveals the early vertebrate proto-karyotype. Nature 431(7011):946–957. https://doi.org/10.1038/nature03025 CrossRefPubMedGoogle Scholar
- Qi D, Chao Y, Guo S, Zhao L, Li T, Wei F, Zhao X (2012) Convergent, parallel and correlated evolution of trophic morphologies in the subfamily schizothoracinae from the Qinghai-Tibetan plateau. PLoS One 7(3):e34070. https://doi.org/10.1371/journal.pone.0034070 CrossRefPubMedPubMedCentralGoogle Scholar
- Saitoh K, Sado T, Mayden RL, Hanzawa N, Nakamura K, Nishida M, Miya M (2006) Mitogenomic evolution and interrelationships of the Cypriniformes (Actinopterygii: Ostariophysi): the first evidence toward resolution of higher-level relationships of the world's largest freshwater fish clade based on 59 whole mitogenome sequences. J Mol Evol 63(6):826–841. https://doi.org/10.1007/s00239-005-0293-y CrossRefPubMedGoogle Scholar
- Saroglia M, Terova G, De Stradis A, Caputo A (2002) Morphometric adaptations of sea bass gills to different dissolved oxygen partial pressures. J Fish Biol 60(6):1423–1430. https://doi.org/10.1111/j.1095-8649.2002.tb02437.x CrossRefGoogle Scholar
- Schrodinger LLC (2010) The PyMOL Molecular Graphics System, Version 184.108.40.206Google Scholar
- Smith RW, Houlihan DF, Nilsson GE, Brechin JG (1996) Tissue-specific changes in protein synthesis rates in vivo during anoxia in crucian carp. Am J Phys 271:R897–R904Google Scholar
- Swofford DL (2000) PAUP*. Phylogenetic Analysis Using Parsimony (*and other methods). Version 4. Massachusetts: Sinauer, SunderlandGoogle Scholar
- Ton C, Stamatiou D, Liew CC (2003) Gene expression profile of zebrafish exposed to hypoxia during development. Physiol Genomics 13(2):97–106. https://doi.org/10.1152/physiolgenomics.00128.2002 CrossRefPubMedGoogle Scholar
- Wu YF, Wu CZ (1992) The fishes of the Qinghai-Xizang plateau. Science and Technology Press, ChengduGoogle Scholar
- Wunderlich C, Flogel U, Godecke A, Heger J, Schrader J (2003) Acute inhibition of myoglobin impairs contractility and energy state of iNOS-overexpressing hearts. Circ Res 92(12):1352–1358. https://doi.org/10.1161/01.RES.0000079026.70629.E5 CrossRefPubMedGoogle Scholar
- Yang ZH, Nielsen R (2002) Codon-substitution models for detecting molecular adaptation at individual sites along specific lineages. Mol Biol Evol 19(6):908–917. https://doi.org/10.1093/oxfordjournals.molbev.a004148 CrossRefPubMedGoogle Scholar