The Number and Transmission of [PSI+] Prion Seeds (Propagons) in the Yeast Saccharomyces Cerevisiae

Byrne, Lee J. and Cole, Diana J. and Cox, Brian S. and Ridout, Martin S. and Morgan, Byron J. T. and Tuite, Mick F. (2009) The Number and Transmission of [PSI+] Prion Seeds (Propagons) in the Yeast Saccharomyces Cerevisiae. PLoS ONE , Online . ISSN eISSN-1932-6203. (The full text of this publication is not available from this repository)

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http://www.plosone.org/article/info%3Adoi%2F10.137...

Abstract

Abstract Top Background Yeast (Saccharomyces cerevisiae) prions are efficiently propagated and the on-going generation and transmission of prion seeds (propagons) to daughter cells during cell division ensures a high degree of mitotic stability. The reversible inhibition of the molecular chaperone Hsp104p by guanidine hydrochloride (GdnHCl) results in cell division-dependent elimination of yeast prions due to a block in propagon generation and the subsequent dilution out of propagons by cell division. Principal Findings Analysing the kinetics of the GdnHCl-induced elimination of the yeast [PSI+] prion has allowed us to develop novel statistical models that aid our understanding of prion propagation in yeast cells. Here we describe the application of a new stochastic model that allows us to estimate more accurately the mean number of propagons in a [PSI+] cell. To achieve this accuracy we also experimentally determine key cell reproduction parameters and show that the presence of the [PSI+] prion has no impact on these key processes. Additionally, we experimentally determine the proportion of propagons transmitted to a daughter cell and show this reflects the relative cell volume of mother and daughter cells at cell division. Conclusions While propagon generation is an ATP-driven process, the partition of propagons to daughter cells occurs by passive transfer via the distribution of cytoplasm. Furthermore, our new estimates of n0, the number of propagons per cell (500–1000), are some five times higher than our previous estimates and this has important implications for our understanding of the inheritance of the [PSI+] and the spontaneous formation of prion-free cells.

Item Type: Article
Additional information: Research Article
Subjects: Q Science > QA Mathematics (inc Computing science) > QA276 Mathematical statistics
Q Science > QK Botany
Q Science > QR Microbiology
Q Science > QP Physiology (Living systems) > QP506 Molecular biology
Divisions: Faculties > Science Technology and Medical Studies > School of Mathematics Statistics and Actuarial Science > Statistics
Faculties > Science Technology and Medical Studies > School of Biosciences > Protein Science Group
Depositing User: Diana Cole
Date Deposited: 26 Oct 2009 12:52
Last Modified: 14 May 2014 15:25
Resource URI: http://kar.kent.ac.uk/id/eprint/23092 (The current URI for this page, for reference purposes)
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