title: Novel class of nuclear genes involved in both mRNA splicing and protein synthesis in Saccharomyces cerevisiae mitochondria.
abstract: We have cloned three distinct nuclear genes, NAM1, NAM7, and NAM8, which alleviate mitochondrial intron mutations of the cytochrome b and COXI (subunit I of cytochrome oxidase) genes when present on multicopy plasmids. These nuclear genes show no sequence homology to each other and are localized on different chromosomes: NAM1 on chromosome IV, NAM7 on chromosome XIII and NAM8 on chromosome VIII. Sequence analysis of the NAM1 gene shows that it encodes a protein of 440 amino acids with a typical presequence that would target the protein to the mitochondrial matrix. Inactivation of the NAM1 gene by gene transplacement leads to a dramatic reduction of the overall synthesis of mitochondrial protein, and a complete absence of the COXI protein which is the result of a specific block in COXI pre-mRNA splicing. The possible mechanisms by which the NAM1 gene product may function are discussed.
authors.affiliation: Centre de Génétique Moléculaire du C.N.R.S., Laboratoire propre associé à l'Université P. et M. Curie, Gif-sur-Yvette, France.
authors.forename: E B
authors.initials: EB
authors.lastname: Asher
authors.forename: O
authors.initials: O
authors.lastname: Groudinsky
authors.forename: G
authors.initials: G
authors.lastname: Dujardin
authors.forename: N
authors.initials: N
authors.lastname: Altamura
authors.forename: M
authors.initials: M
authors.lastname: Kermorgant
authors.forename: P P
authors.initials: PP
authors.lastname: Slonimski
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D002467:Cell Nucleus / Q000378:metabolism; D004271:DNA, Fungal / Q000235:genetics; D005656:Fungal Proteins / Q000096:biosynthesis / Q000235:genetics; D005800:Genes, Fungal; D008928:Mitochondria / Q000378:metabolism; D008969:Molecular Sequence Data; D012326:RNA Splicing; D012331:RNA, Fungal / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D015183:Restriction Mapping; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000378:metabolism; D012689:Sequence Homology, Nucleic Acid; D013489:Suppression, Genetic; D014158:Transcription, Genetic
chemical_list: D004271:DNA, Fungal; D005656:Fungal Proteins; D012331:RNA, Fungal; D012333:RNA, Messenger