Section 48
Chapter 47,575

The [URE3] prion is an aggregated form of Ure2p that can be cured by overexpression of Ure2p fragments

Edskes, H.K.; Gray, V.T.; Wickner, R.B.

Proceedings of the National Academy of Sciences of the United States of America 96(4): 1498-1503


ISSN/ISBN: 0027-8424
PMID: 9990052
DOI: 10.1073/pnas.96.4.1498
Accession: 047574726

The [URE3] nonchromosomal genetic element is a prion of Ure2p, a regulator of nitrogen catabolism in Saccharomyces cerevisiae. Ure2p1-65 is the prion domain of Ure2p, sufficient to propagate [URE3] in vivo. We show that full length Ure2p-green fluorescent protein (GFP) or a Ure2p1-65-GFP fusion protein is aggregated in cells carrying [URE3] but is evenly distributed in cells lacking the [URE3] prion. This indicates that [URE3] involves a self-propagating aggregation of Ure2p. Overexpression of Ure2p1-65 induces the de novo appearance of [URE3] by 1,000-fold in a strain initially [ure-o], but cures [URE3] from a strain initially carrying the [URE3] prion. Overexpression of several other fragments of Ure2p or Ure2-GFP fusion proteins also efficiently cures the prion. We suggest that incorporation of fragments or fusion proteins into a putative [URE3] "crystal" of Ure2p poisons its propagation.

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