|The [URE3] prion is not conserved among Saccharomyces species. [MANUSCRIPT]|
Talarek N, Maillet L, Cullin C, Aigle M
Category: prions ¤ Added: Sep 02, 2005 ¤ Rating: ◊◊
The [URE3] prion of Saccharomyces cerevisiae is a self-propagating inactive form of the nitrogen catabolism regulator Ure2p. To determine whether the [URE3] prion is conserved in S. cerevisiae related yeast species we have developed genetic tools allowing the detection of [URE3] in Saccharomyces paradoxus and Saccharomyces uvarum. We found that [URE3] is conserved in S. uvarum. In contrast, [URE3] was not detected in S. paradoxus. The inability of S. paradoxus Ure2p to switch to a prion isoform results from the primary sequence of the protein and not from the lack of cellular co-factors as heterologous Ure2p can propagate [URE3] in this species. Our data therefore demonstrate that [URE3] is conserved only in a subset of Saccharomyces species. Implications of our finding on the physiological and evolutive meaning of yeast [URE3] prion are discussed.