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Proc Natl Acad Sci U S A

Title:		Cell division is essential for elimination of the yeast [PSI+] prion by guanidine hydrochloride
Author(s):		Byrne LJ; Cox BS; Cole DJ; Ridout MS; Morgan BJ; Tuite MF;
Address:		"Protein Science Group, Department of Biosciences, University of Kent, Canterbury CT2 7NJ, United Kingdom"
Journal Title:		Proc Natl Acad Sci U S A
Year:		2007
Volume:		20070702
Issue:		28
Page Number:		11688 - 11693
DOI:		10.1073/pnas.0701392104
ISSN/ISBN:		0027-8424 (Print) 1091-6490 (Electronic) 0027-8424 (Linking)
Abstract:		"Guanidine hydrochloride (Gdn.HCl) blocks the propagation of yeast prions by inhibiting Hsp104, a molecular chaperone that is absolutely required for yeast prion propagation. We had previously proposed that ongoing cell division is required for Gdn.HCl-induced loss of the [PSI+] prion. Subsequently, Wu et al.[Wu Y, Greene LE, Masison DC, Eisenberg E (2005) Proc Natl Acad Sci USA 102:12789-12794] claimed to show that Gdn.HCl can eliminate the [PSI+] prion from alpha-factor-arrested cells leading them to propose that in Gdn.HCl-treated cells the prion aggregates are degraded by an Hsp104-independent mechanism. Here we demonstrate that the results of Wu et al. can be explained by an unusually high rate of alpha-factor-induced cell death in the [PSI+] strain (780-1D) used in their studies. What appeared to be no growth in their experiments was actually no increase in total cell number in a dividing culture through a counterbalancing level of cell death. Using media-exchange experiments, we provide further support for our original proposal that elimination of the [PSI+] prion by Gdn.HCl requires ongoing cell division and that prions are not destroyed during or after the evident curing phase"
Keywords:		"Cell Division/*physiology Guanidine/*pharmacology Mating Factor Models, Biological Peptides/physiology Prions/*drug effects Saccharomyces cerevisiae/*cytology/*drug effects/physiology;"
Notes:		"MedlineByrne, Lee J Cox, Brian S Cole, Diana J Ridout, Martin S Morgan, Byron J T Tuite, Mick F eng E18382/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom Comparative Study Research Support, Non-U.S. Gov't 2007/07/04 Proc Natl Acad Sci U S A. 2007 Jul 10; 104(28):11688-93. doi: 10.1073/pnas.0701392104. Epub 2007 Jul 2"