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Hypoxia-inducible myoglobin expression in nonmuscle tissues
- Jane Fraser*,
- Luciane Vieira de Mello*,†,
- Deborah Ward*,
- Huw H. Rees*,
- Daryl R. Williams*,
- Yongchang Fang‡,
- Andrew Brass‡,
- Andrew Y. Gracey*,§, and
- Andrew R. Cossins*,¶
- *School of Biological Sciences, University of Liverpool, Liverpool L69 7ZB, United Kingdom;
- †School of Biological Sciences, University of Manchester, Manchester M13 9PL, United Kingdom; and
- ‡Embrapa Recursos Genéticos e Biotecnologia, Brasília, Brazil 70770-900
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Edited by George N. Somero, Stanford University, Pacific Grove, CA, and approved December 23, 2005 (received for review September 22, 2005)
Abstract
Myoglobin (Myg) is an oxygen-binding hemoprotein that is widely thought to be expressed exclusively in oxidative skeletal and cardiac myocytes, where it plays a key role in coping with chronic hypoxia. We now show in a hypoxia-tolerant fish model, that Myg is also expressed in a range of other tissues, including liver, gill, and brain. Moreover, expression of Myg transcript was substantially enhanced during chronic hypoxia, the fold-change induction being far greater in liver than muscle. By using 2D gel electrophoresis, we have confirmed that liver expresses a protein corresponding to the Myg-1 transcript and that it is significantly up-regulated during hypoxia. We have also discovered a second, unique Myg isoform, distinct from neuroglobin, which is expressed exclusively in the neural tissue but whose transcript expression was unaffected by environmental hypoxia. Both observations of nonmuscle expression and a brain-specific isoform are unprecedented, indicating that Myg may play a much wider role than previously understood and that Myg might function in the protection of tissues from deep hypoxia and ischemia as well as in reoxygenation and reperfusion injury.
Footnotes
- ¶To whom correspondence should be addressed. E-mail: cossins{at}liv.ac.uk
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↵ §Present address: Marine Environmental Biology, University of Southern California, Los Angeles, CA 90089-0371.
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Author contributions: J.F., H.R.R., A.Y.G., and A.R.C. designed research; J.F., L.V.d.M., D.W., D.R.W., and A.Y.G. performed research; H.R.R., Y.F., and A.B. contributed new reagents/analytic tools; J.F., L.V.d.M., Y.F., A.B., and A.Y.G. analyzed data; and A.R.C. wrote the paper.
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Conflict of interest statement: No conflicts declared.
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This paper was submitted directly (Track II) to the PNAS office.
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Data deposition: The sequence reported in this paper has been deposited in the GenBank database (accession no. DQ338464). The microarray data files are available in the ArrayExpress database (accession no. E-MAXD-10).
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See Commentary on page 2469.
- Abbreviation:
- Myg,
- myoglobin.
- © 2006 by The National Academy of Sciences of the USA
