An essential yeast protein, encoded by duplicated genes TIF1 and TIF2 and homologous to the mammalian translation initiation factor eIF-4A, can suppress a mitochondrial missense mutation.
We describe the isolation and characterization of two previously undescribed genes, TIF1 and TIF2, from Saccharomyces cerevisiae. The protein-encoding sequences of the two genes are highly conserved, resulting in two completely identical proteins, whereas the flanking regions show no obvious homology. The two yeast proteins are highly similar to the translation initiation factor eIF-4A from mouse. Elevated gene dosage of TIF1 or TIF2 results in the suppression of a missense mutation in the mitochondrial oxi2 gene, which codes for subunit III of cytochrome-c oxidase, although the sequence of the Tif protein indicates its cytoplasmic localization. Inactivation of either gene by gene disruption has no effect on cell viability or on mitochondrial functions. However, simultaneous inactivation of both genes is lethal to the cell.
Linder
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Centre de Génétique Moléculaire du Centre National de la Recherche Scientifique, Université Pierre et Marie Curie, Gif-sur-Yvette, France.
Slonimski
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D000595:Amino Acid Sequence; D001483:Base Sequence; D004272:DNA, Mitochondrial / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics; D039601:Eukaryotic Initiation Factor-4A; D005656:Fungal Proteins / Q000235:genetics*; D005796:Genes; D005800:Genes, Fungal; D005838:Genotype; D008969:Molecular Sequence Data; D005810:Multigene Family; D010448:Peptide Initiation Factors / Q000235:genetics*; D010957:Plasmids; D015183:Restriction Mapping; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000254:growth & development; D012689:Sequence Homology, Nucleic Acid
D004272:DNA, Mitochondrial; D005656:Fungal Proteins; D010448:Peptide Initiation Factors; D039601:Eukaryotic Initiation Factor-4A