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EN
Maf1 was the first protein discovered to regulate polymerase III RNA in yeast and because it is evolutionarily conserved, a Maf1 ortholog also serves to restrain transcription in mouse and human cells. Understanding the mechanism of the regulation has been made possible by recent studies showing that Maf1 is a nuclear/cytoplasmic protein whose subcellular distribution and hence negative regulation of Pol III transcription is mediated by the nutrient-sensing signaling pathways, TOR and RAS. Under stress conditions and during growth in a nonfermentable carbon source Maf1 is dephosphorylated and imported to the nucleus. In its non-phosphorylated form, Maf1 interacts with the polymerase III transcription machinery. Phosphorylation serves to locate Maf1 to the cytoplasm under favorable growth conditions, thereby preventing it from non-negatively regulating polymerase III when high levels of tRNA transcription are required. Relocation of Maf1 to the cytoplasm is dependent on Msn5, a carrier responsible for export of several other phosphoproteins out of the nucleus. The absence of Maf1-mediated control of tRNA synthesis impairs yeast viability in nonfermentable carbon sources. Moreover, in cells grown in a nonfer mentable carbon source, Maf1 regulates the levels of different tRNAs to various extents. This differential regulation may contribute to the physiological role of Maf1.
EN
In contrast to most other eukaryotic organisms, yeast can survive without respiration. This ability has been exploited to investigate nuclear genes required for expression of mitochondrial DNA. Availability of complete Saccharomyces cerevisiae genomic sequence has provided additional help in detailed molecular analysis. Seven of the eight major products encoded by mitochondrial DNA are hydrophobic subunits of respiratory complexes in the inner membrane. Localization of the translation process in the same cellular compartment ensures synthesis of mitochondrially encoded proteins near sites of their assembly into multimeric respiratory complexes. Association of mitochondrial ribosomes with the membrane is mediated by mRNA-specific translational activators, that are involved in the recognition of initation codon. The newly synthesized mitochondrial proteins are transferred to membrane by a specific export system. This review discusses the role of membrane-localized factors responsible for quality control and turnover of mitochondrially synthesized subunits as well as for assembly of respiratory complexes.
EN
The relations between attributes describing the Board of Directors and the economic performance of a relevant company, and that of the sectors in national economy are investigated. The Principal - Agent Theory and the Game Theory cannot be used in satisfactory way to verify economic behavior arising in particular situations, because they operate on general concepts. The paper presents an attempt to reformulate this issue, taking it into account when explaining the process of operational decision making. The usual focus on what the Boards of Directors do, how their composition may affect it, and what should be done to improve their effectiveness is extended to include the issue of criteria used in Board selection process. Search for empirical regularity within director's selection process leads to learn how directors are chosen and to understanding corporate organization and governance.
16
Content available remote Influence of the Education on the Level of Unemployment in European Countries
51%
EN
The results of an empirical survey on the relationship between unemployment rate and selected macroeconomic indicators are presented. The goal of the analysis was to verify the hypothesis on significant correlation of the level of unemployment and the society's level of education. In addition, an investigation on the strength of the relationship between unemployment level and education linked with labor policy was conducted. Two hypotheses were investigated. The first one states that within the group of 29 surveyed countries separate subgroups, internally coherent can be distinguished. The second hypothesis postulates that the unemployment rate depends stronger on the level of expenditures and other indicators linked to education or development than on active labor market policies.
EN
Yeast mitochondrial DNA codes for eight major polypeptides. Translation of he mitochondrially encoded polypeptides in strains with mutated mitochondrial release factor, mRF1, was found to result in the synthesis of a novel protein, V2. Different mrf1 alleles were associated with different efficiency of V2p synthesis. Translation of V2p was enhanced by paromomycin. Comparative analysis of peptides resulting from protease digestion indicated that V2p is a derivative of Var1p. According to our hypothesis, V2p represents a readthrough product of the natural stop codon in VAR1 mRNA.
EN
We studied expression of the NAM9 gene of Saccharomyces cerevisiae that was previously reported to code for a mitochondrial ribosomal protein. Increase in NAM9 gene dosage is accompanied by the increase in both mRNA and protein. The levels of the NAM9 transcript and protein are both reduced in cells growing on glucose as compared to cells growing on galactose as a carbon source. Nam9p accumulates to the same level in rho(o) and rho(+) cells. These results confirm previous data indicating diverse regulation of different mitochondrial ribosomal protein genes and suggest that expression of Nam9p is not co-ordinated with the expression of other mitochondrial ribosomal components.
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