A Discrete-Time Branching Process Model of Yeast Prion Curing Curves*

Abstract

The infectious agent of many neurodegenerative disorders is thought to be aggregates of prion protein, which are transmitted between cells. Recent work in yeast supports this hypothesis but also suggests that only aggregates below a critical size are transmitted efficiently. The total number of transmissible aggregates in a typical cell is a key determinant of strain infectivity.

In a discrete-time branching process model of a yeast colony with prions, prion aggregates increase in size according to a Poisson process and only aggregates below a threshold size are transmitted during cell division. The total number of cells with aggregates in a growing population of yeast is expressed.

Keywords:

• branching process
• curing curves
• Poisson process
• prion
• yeast

ACKNOWLEDGMENTS

The work was supported by NIH grant 1R15GM093957-01 to Peter Oloffson and NIH grant 1F32GM089049-01 to Suzanne S. Sindi.

Notes

*Communicated by Peter Jagers and Christine Jacob.