Prion proteins as genetic material in fungi

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Prion proteins as genetic material in fungi

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Benkemouna and Sven J. Saupe, a,

aLaboratoire de Génétique Moléculaire des Champignons, Institut de

Biochimie et de Génétique Cellulaires, UMR 5095 CNRS/Université de

Bordeaux 2, 1 rue Camille St Saëns, 33077 Bordeaux cedex, France

Received 13 April 2006; accepted 3 June 2006. Available online 9

August 2006.

Abstract

Prions are infectious proteins. Several prions have been identified

in fungi where they behave as non-Mendelian cytoplasmic genetic

elements. Most of these prions propagate as self-perpetuating

amyloid aggregates thus providing an example of structural heredity.

In yeast, prion propagation requires the Hsp104 disaggregase

presumably to sheer amyloid assemblies and generate more fiber ends.

Recent work in yeast shows that amyloid structure polymorphism

underlies the prion strain phenomenon and influences species

barriers. Structural models for the amyloid form of several fungal

prion proteins are now available. All propose a cross & #946;-organization

with parallel & #946;-sheets. Whether or not some of the fungal prions

might be beneficial to their host is still a debated issue.

Keywords: Prion; Amyloid; Non-Mendelian genetics; Fungi; Structural

heredity

Corresponding author. Fax: +33 0 5 56 99 90 67.