NR APAK
AU Westaway,D.; Drisaldi,B.; Coomaraswamy,J.; Mastrangelo,P.; Strome,B.; Yang,J.
TI A cellular assay for Prnd/Prnp interactions: genetic mapping of active regions in PrPc and Doppel
QU International Conference - Prion diseases: from basic research to intervention concepts - TSE-Forum, 08.10.-10.10.2003, Gasteig, München - Oral sessions OS-17
PT Konferenz-Vortrag
AB The function of PrPc has proven a long-standing puzzle in prion biology. Doppel (Dpl), a recently discovered PrP-like protein encoded by the Prnd gene, is expressed in the testis but produces apoptosis when expressed in cerebellar neurons. This effect is antagonized by expression of wt PrPc. Here we have used four types of alleles previously tested in transgenic mice to establish an assay for Prnp/Prnd epistasis that is compatible with saturation mutagenesis. Using a bigenic GFP vector to drive expression in cerebellar granule cells, N-terminally deleted Prnp alleles did not protect against the pro-apoptotic action of Dpl. Conversely, two Prnd alleles with overlapping deletions in the central region of the Dpl open reading frame were inactive. Inactivation of GPI-anchor signal peptide sequences neither diminished the protective activity of Prnp nor the pro-apoptotic action of Prnd. These data are difficult to reconcile with the hypothesis that surface-anchored Dpl and PrPc compete by virtue of displaying high affinity sites for a shared extracellular ligand. Although the molecular mechanism underlying Prnp/Prnd interactions remains enigmatic, further iterations of the cellular assay described here may provide definitive insights into this process.
AD David Westaway, Bettina Drisaldi, Janaky Coomaraswamy, Peter Mastrangelo, Bob Strome, Jing Yang, Howard TJ Mount, University of Toronto, Canada
SP englisch
PO Deutschland