Affiliation: | (1) Molekulare Genetik der Universität Heidelberg, Im Neuenheimer Feld 230, D-6900 Heidelberg, Germany;(2) Cell Biology Group, Worcester Foundation for Experimental Biology, 01545 Shrewsbury, MA, USA;(3) Present address: Department of Biochemistry and Molecular Biology, Harvard University, 7 Divinity Avenue, 02138 Cambridge, MA, USA |