[1] Ruhr Univ Bochum, Inst Physiol Chem, D-44780 Bochum, Germany
[2] NCI, Mammalian Genet Lab, ABL Basic Res Program, Frederick Canc Res & Dev Ctr, Frederick, MD 21702 USA
[3] Univ Marburg, Fachbereich Med, Abt Allgeneine Humangenet, D-35037 Marburg, Germany
[4] Ruhr Univ Bochum, Inst Physiol Chem, D-44780 Bochum, Germany