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The yeast non-Mendelian factor [psi+] has been suggested to be a self-modified protein analogous to mammalian prions. Here it is reported that an intermediate amount of the chaperone protein Hsp104 was required for the propagation of the [psi+] factor. Over-production or inactivation of Hsp104 caused the loss of [psi+]. These results suggest that chaperone(More)
We describe a new ab initio algorithm, GeneMark-ES version 2, that identifies protein-coding genes in fungal genomes. The algorithm does not require a predetermined training set to estimate parameters of the underlying hidden Markov model (HMM). Instead, the anonymous genomic sequence in question is used as an input for iterative unsupervised training. The(More)
Finding new protein-coding genes is one of the most important goals of eukaryotic genome sequencing projects. However, genomic organization of novel eukaryotic genomes is diverse and ab initio gene finding tools tuned up for previously studied species are rarely suitable for efficacious gene hunting in DNA sequences of a new genome. Gene identification(More)
Propagation of the yeast protein-based non-Mendelian element [PSI], a prion-like form of the release factor Sup35, was shown to be regulated by the interplay between chaperone proteins Hsp104 and Hsp70. While overproduction of Hsp104 protein cures cells of [PSI], overproduction of the Ssa1 protein of the Hsp70 family protects [PSI] from the curing effect of(More)
We have previously shown that multicopy plasmids containing the complete SUP35 gene are able to induce the appearance of the non-Mendelian factor [PSI]. This result was later interpreted by others as a crucial piece of evidence for a model postulating that [PSI] is a self-modified, prion-like conformational derivative of the Sup35 protein. Here we support(More)
Saccharomyces cerevisiae prion [PSI ] is a self-propagating isoform of the eukaryotic release factor eRF3 (Sup35p). Sup35p consists of the evolutionary conserved release factor domain (Sup35C) and two evolutionary variable regions - Sup35N, which serves as a prion-forming domain in S. cerevisiae, and Sup35M. Here, we demonstrate that the prion form of(More)
[PSI(+)] is a prion isoform of the yeast release factor Sup35. In some assays, the cytosolic chaperones Ssa1 and Ssb1/2 of the Hsp70 family were previously shown to exhibit "pro-[PSI(+)]" and "anti-[PSI(+)]" effects, respectively. Here, it is demonstrated for the first time that excess Ssa1 increases de novo formation of [PSI(+)] and that pro-[PSI(+)](More)
In mammalian cells, abnormal proteins that escape proteasome-dependent degradation form small aggregates that can be transported into a centrosome-associated structure, called an aggresome. Here we demonstrate that in yeast a single aggregate formed by the huntingtin exon 1 with an expanded polyglutamine domain (103QP) represents a bona fide aggresome that(More)
Mutation of the mouse Usp14 gene, encoding the homolog of yeast deubiquitinating enzyme Ubp6, causes ataxia. Here we show that deletion of the UBP6 gene in Saccharomyces cerevisiae causes sensitivity to a broad range of toxic compounds and antagonizes phenotypic expression and de novo induction of the yeast prion [PSI+], a functionally defective(More)
The maintenance of [PSI], a prion-like form of the yeast release factor Sup35, requires a specific concentration of the chaperone protein Hsp104: either deletion or overexpression of Hsp104 will cure cells of [PSI]. A major puzzle of these studies was that overexpression of Hsp104 alone, from a heterologous promoter, cures cells of [PSI] very efficiently,(More)