[1] Deutsch Krebsforschungszentrum, Dept Immunochem, D-69120 Heidelberg, Germany
[2] Karolinska Inst, Novum, Dept Med Nutr, S-14157 Huddinge, Sweden
[3] Netherlands Inst Dev Biol, Hubrecht Lab, NL-3584 CT Utrecht, Netherlands
[4] Forschungszentrum Karlsruhe, Dept Genet, D-76021 Karlsruhe, Germany
[5] VIB, Mol Biol Lab, B-9000 Ghent, Belgium