title: In vitro and in vivo studies on the mitochondrial import of CBS1, a translational activator of cytochrome b in yeast.
abstract: Translation of mitochondrial cytochrome b mRNA in yeast is activated by the product of the nuclear gene CBS1. CBS1 encodes a 27 kDa precursor protein, which is cleaved to a 24 kDa mature protein during the import into isolated mitochondria. The sequences required for mitochondrial import reside in the amino-terminal end of the CBS1 precursor. Deletion of the 76 amino-terminal amino acids renders the protein incompetent for mitochondrial import in vitro and non-functional in vivo. When present on a high copy number plasmid and under the control of a strong yeast promoter, biological function can be restored by this truncated derivative. This observation indicates that the CBS1 protein devoid of mitochondrial targeting sequences can enter mitochondria in vivo, possibly due to a bypass of the mitochondrial import system.
authors.affiliation: Institut für Genetik und Mikrobiologie der Universität München, Federal Republic of Germany.
authors.forename: A
authors.initials: A
authors.lastname: Körte
authors.forename: V
authors.initials: V
authors.lastname: Forsbach
authors.forename: T
authors.initials: T
authors.lastname: Gottenöf
authors.forename: G
authors.initials: G
authors.lastname: Rödel
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D001692:Biological Transport; D003573:Cytochrome b Group / Q000096:biosynthesis* / Q000235:genetics; D004271:DNA, Fungal / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D005786:Gene Expression Regulation; D005800:Genes, Fungal; D008928:Mitochondria / Q000378:metabolism*; D024101:Mitochondrial Proteins; D008969:Molecular Sequence Data; D010957:Plasmids; D014176:Protein Biosynthesis; D011498:Protein Precursors / Q000096:biosynthesis* / Q000235:genetics; D012331:RNA, Fungal / Q000096:biosynthesis; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins; D012995:Solubility; D015534:Trans-Activators
chemical_list: C060724:CBS1 protein, S cerevisiae; D003573:Cytochrome b Group; D004271:DNA, Fungal; D005656:Fungal Proteins; D024101:Mitochondrial Proteins; D011498:Protein Precursors; D012331:RNA, Fungal; D029701:Saccharomyces cerevisiae Proteins; D015534:Trans-Activators