NR AOQQ
AU Brachmann,A.; Wickner,R.B.
TI Saccharomyces cerevisiae as a model system for amyloid formation in vivo
QU International Conference - Prion diseases: from basic research to intervention concepts - TSE-Forum, 08.10.-10.10.2003, Gasteig, München - Poster session - BR-16
PT Konferenz-Poster
AB Genetic evidence identified the non-chromosomal element [URE3] of Saccharomyces cerevisiae to be a prion form of Ure2p, a protein involved in nitrogen catabolite repression. Native Ure2p binds to the transcription factor Gln3p, thereby inhibiting the transcription of a number of genes required for the use of poor nitrogen sources. One of these genes is DAL5, encoding an allantoate transporter. Ure2p consists of a C-terminal region sufficient for the repression function and an asparagine and glutamine rich region at the N-terminus that can undergo amyloid formation, leading to infectious aggregates. Therefore in [URE3] cells Ure2p is inactivated and Gln3p is able to turn on the DAL5 promoter. We used this promoter in fusion with various reporter genes to construct S. cerevisiae strains in which genetic selection could be performed for, as well as against, Ure2p activity. This enabled us to create functional fusion constructs between different amyloid forming peptides and the C-terminal part of Ure2p. So far we have made fusion proteins with peptides from amylin (type II diabetes), serum amyloid A (secondary systemic amyloidosis), amyloid beta (Alzheimer's disease), alpha-synuclein (Parkinson's disease), transthyretin (senile systemic amyloidosis), and amino acids 22 to 231 of mouse PrP. We are currently trying to establish conditions under which these fusion proteins undergo amyloid formation in vivo and establish themselves as prions in S. cerevisiae. This model system could be employed in genetic screens for the discovery and investigation of cellular factors contributing to and preventing amyloid formation, as well as to compare differences between various amyloidogenic peptides. Furthermore it would be useful for the detection of new potential prion proteins from diverse organisms.
AD Andreas Brachmann, Reed B. Wickner, Laboratory of Biochemsitry and Genetics, NIDDK, National Institutes of Health; Bethesda, MD; USA
SP englisch
PO Deutschland