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Vol 43(2009) N 3 p. 360-366; T.M. Rogoza, O.V. Viktorovskaya, S.A. Rodionova, M.S. Ivanov, K.V. Volkov, L.N. Mironova Search for genes influencing the maintenance of the [ISP+ ] prion-like antisuppressor determinant in yeast with the use of an insertion gene library Department of Genetics and Breeding, St. Petersburg State University, St. Petersburg, 199034, RussiaReceived - 2008-08-18; Accepted - 2008-09-09 The prion-like determinant [ISP+] manifests itself as an antisuppressor of certainsup35 mutations. To establish that [ISP+] is indeed a new yeast prion, it is necessary to identify the gene that codes for the protein whose prion form is [ISP+]. Analysis of the transformants obtained by transformation of an [ISP+] strain with an insertion gene library revealed three genes controlling the [ISP+] maintenance: UPF1, UPF2, and SFP1. SFP1 codes for a potentially prionogenic protein, which is enriched in Asn and Gln residues, and is thereby the most likely candidate for the [ISP+] structural gene. UPF1 and UPF2 code for components of nonsense-mediated mRNA decay. The [ISP+] elimination caused by UPF1 and UPF2 inactivation was reversible, and Upf1p and Upf2p were not functionally related to phosphatase Ppz1p, which influences the [ISP+] manifestation. Possible mechanisms sustaining the influence of UPF1 and UPF2 on [ISP+] maintenance are discussed. Yeast, nonsense suppression, yeast prions, insertion gene library, UPF1, UPF2, SFP1, PPZ1 |
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