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Expression of selected genes escaping from X inactivation in the 41, XXY* mouse model for Klinefelter’s syndrome

Authors

  • Steffi Werler,

    1. Institute of Reproductive and Regenerative Biology, Centre of Reproductive Medicine and Andrology, University Clinics, Muenster, Germany
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  • Andreas Poplinski,

    1. Institute of Reproductive and Regenerative Biology, Centre of Reproductive Medicine and Andrology, University Clinics, Muenster, Germany
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  • Jörg Gromoll,

    1. Institute of Reproductive and Regenerative Biology, Centre of Reproductive Medicine and Andrology, University Clinics, Muenster, Germany
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  • Joachim Wistuba

    1. Institute of Reproductive and Regenerative Biology, Centre of Reproductive Medicine and Andrology, University Clinics, Muenster, Germany
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Dr. Joachim Wistuba, Centre of Reproductive Medicine and Andrology, University Clinics, Domagkstrasse 11, 48149 Muenster, Germany.
Tel: +49-[0]251-83-52043 |
Fax: +49-[0]251-83-54800 |
Email: joachim.wistuba@ukmuenster.de

Abstract

Aim:  We hypothesized that patients with Klinefelter’s syndrome (KS) not only undergo X inactivation, but also that genes escape from inactivation. Their transcripts would constitute a significant difference, as male metabolism is not adapted to a ‘female-like’ gene dosage. We evaluated the expression of selected X-linked genes in our 41, XXY* male mice to determine whether these genes escape inactivation and whether tissue-specific differences occur.

Methods:  Correct X inactivation was identified by Xist expression. Relative expression of X-linked genes was examined in liver, kidney and brain tissue by real-time PCR in adult XXY* and XY* males and XX females.

Results:  Expression of genes known to escape X inactivation was analysed. Relative mRNA levels of Pgk1 (control, X inactivated), and the genes Eif2s3x, Kdm5c, Ddx3x and Kdm6a escaping from X inactivation were quantified from liver, kidney and brain. Pgk1 mRNA expression showed no difference, confirming correct X inactivation. In kidney and liver, XXY* males resembled the female expression pattern in all four candidate genes and were distinguishable from XY* males. Contrastingly, in brain tissue XXY* males expressed all four genes higher than male and female controls.

Conclusion:  Altered expression of genes escaping X inactivation probably contributes directly to the XXY* phenotype.

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