Abstract
The [URE3] phenotype in Saccharomyces cerevisiae is caused by the inactive, altered (prion) form of the Ure2 protein (Ure2p), a regulator of nitrogen catabolism. Ure2p has two functional domains: an N-terminal domain necessary and sufficient for prion propagation and a C-terminal domain responsible for nitrogen regulation. We show here that the mRNA encoding Ure2p possesses an IRES (internal ribosome entry site). Internal initiation leads to the synthesis of an N-terminally truncated active form of the protein (amino acids 94-354) lacking the prion-forming domain. Expression of the truncated Ure2p form (94-354) mediated by the IRES element cures yeast cells of the [URE3] phenotype. We assume that the balance between the full-length and truncated (94-354) Ure2p forms plays an important role in yeast cell physiology and differentiation.
Publication types
-
Research Support, Non-U.S. Gov't
-
Research Support, U.S. Gov't, P.H.S.
MeSH terms
-
Animals
-
Cell Size
-
Codon, Initiator
-
Genes, Reporter
-
Glutathione Peroxidase
-
Peptide Chain Initiation, Translational*
-
Phenotype
-
Prions / chemistry
-
Prions / genetics
-
Prions / metabolism*
-
Promoter Regions, Genetic
-
Protein Biosynthesis*
-
Protein Structure, Tertiary
-
RNA, Messenger / genetics
-
RNA, Messenger / metabolism
-
Recombinant Fusion Proteins / genetics
-
Recombinant Fusion Proteins / metabolism
-
Saccharomyces cerevisiae / cytology
-
Saccharomyces cerevisiae / genetics*
-
Saccharomyces cerevisiae / metabolism
-
Saccharomyces cerevisiae Proteins / chemistry
-
Saccharomyces cerevisiae Proteins / genetics
-
Saccharomyces cerevisiae Proteins / metabolism*
-
Untranslated Regions
Substances
-
Codon, Initiator
-
Prions
-
RNA, Messenger
-
Recombinant Fusion Proteins
-
Saccharomyces cerevisiae Proteins
-
Untranslated Regions
-
Glutathione Peroxidase
-
URE2 protein, S cerevisiae