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Acta Physiologica 2013; Volume 207, Supplement 694
92nd Annual Meeting of the German Physiological Society
3/2/2013-3/5/2013
Heidelberg, Germany
A NOVEL OXYGEN-BINDING GLOBIN EXPRESSED IN THE HYPOXIC TESTIS
Abstract number: O49
Hoogewijs
1
*D.
, Ebner
2
B., Germani
3
F., Hoffmann
4
F.G., Fabrizius
2
A., Moens
3
L., Burmester
5
T., Dewilde
3
S., Storz
6
J.F., Santambrogio
1
S., Wenger
1
R.H., Neuhauss
7
S.C.F., Vinogradov
8
S.N., Hankeln
2
T.
1
University of Zürich, Institute of Physiology and Zürich Center for Integrative Human Physiology, Zürich, Switzerland
2
Johannes Gutenberg-University, Institute of Molecular Genetics, Mainz, Germany
3
University of Antwerp, Department of Biomedical Sciences, Antwerp, Belgium
4
Mississippi State University, Department of Biochemistry and Molecular Biology, Mississippi State, United States
5
University of Hamburg, Biocenter Grindel and Zoological Museum, Hamburg, Germany
6
University of Nebraska, School of Biological Sciences, Lincoln, United States
7
University of Zürich, Institute of Molecular Life Sciences and Zürich Center for Integrative Human Physiology, Zürich, Switzerland
8
Wayne State University School of Medicine, Department of Biochemistry and Molecular Biology, Detroit, United States
The testis represents a well organized tissue specialized in sperm cell production, which occurs as a highly ordered differentiation process along a profound gradient of oxygen. Spermatogenesis takes place in the seminiferous tubuli of the testis under a high proliferation rate of spermatogenic stem cells, thereby likely consuming considerable amounts of oxygen. As the seminiferous tubuli are fully avascular, the oxygen partial pressure in the lumen of the tubuli is very low. The influence of the hypoxic gradient on the molecular events during spermatogenesis remains unknown. Here we report the discovery of a conserved hitherto unrecognized family of large chimeric heme-containing oxygen-binding globins and provide evidence for their preferential expression in vertebrate testis tissue. This novel family of chimeric proteins possesses an N-terminal calpain-like domain, an internal, circular permuted globin domain and an IQ calmodulin-binding motif. Putative orthologs are present in more than 30 metazoan genomes, including humans, and in choanoflagellates. Intriguingly, the globin domain satisfies the criteria of a myoglobin-like fold but is rearranged and split into two parts. The recombinantly expressed human globin domain exhibits an absorption spectrum characteristic of hexacoordination of the heme iron atom. As the gene is predominantly expressed in testis tissue in humans, mice, zebrafish and frogs we propose the name “androglobin”. Expression is associated with postmeiotic stages of spermatogenesis and is downregulated by experimental hypoxia. Potential evidence exists for increased gene expression in fertile compared to infertile males.
To cite this abstract, please use the following information:
Acta Physiologica 2013; Volume 207, Supplement 694 :O49