1. Institute of Molecular Biology, University Innsbruck , Technikerstr. 25, A-6020 Innsbruck , Austria
2. Center for Molecular Biosciences , University Innsbruck , Technikerstr. 25, A-6020 Innsbruck , Austria
3. Institute of Molecular Biotechnology of the Austrian Academy of Science (IMBA), Vienna BioCenter (VBC) , Dr. Bohr Gasse 3, 1030 Vienna , Austria