title: The four subunits of mitochondrial respiratory complex II are encoded by multiple nuclear genes and targeted to mitochondria in Arabidopsis thaliana.
abstract: Mitochondrial respiratory complex II contains four subunits: a flavoprotein (SDHI), an iron-sulphur subunit (SDH2) and two membrane anchor subunits (SDH3 and SDH4). We have found that in Arabidopsis thaliana SDH I and SDH3 are encoded by two, and SDH4 by one nuclear genes, respectively. All these encoded polypeptides are found to be imported into isolated plant mitochondria. While both SDHI proteins are highly conserved when compared to their counterparts in other organisms, SDH3 and SDH4 share little similarity with non-plant homologues. Expression of SDH1-1, SDH3 and SDH4 genes was detected in all tissues analysed, with the highest steady-state mRNA levels found in flowers and inflorescences. In contrast, the second SDH1 gene (SDH1-2) is expressed at a low level.
authors.affiliation: Departamento de Genética Molecular y Microbiologá, Facultad de Ciencias Biológicas, P. Universidad Católica de Chile, Santiago.
authors.forename: Pablo
authors.initials: P
authors.lastname: Figueroa
authors.forename: Gabriel
authors.initials: G
authors.lastname: Léon
authors.forename: Alvaro
authors.initials: A
authors.lastname: Elorza
authors.forename: Loreto
authors.initials: L
authors.lastname: Holuigue
authors.forename: Alejandro
authors.initials: A
authors.lastname: Araya
authors.forename: Xavier
authors.initials: X
authors.lastname: Jordana
mesh_terms: D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000201:enzymology* / Q000235:genetics; D001692:Biological Transport; D042963:Electron Transport Complex II; D005091:Exons; D015971:Gene Expression Regulation, Enzymologic; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant / Q000235:genetics; D007438:Introns; D008928:Mitochondria / Q000201:enzymology*; D008969:Molecular Sequence Data; D009097:Multienzyme Complexes / Q000235:genetics* / Q000378:metabolism; D009687:Nuclear Proteins / Q000235:genetics* / Q000378:metabolism; D010088:Oxidoreductases / Q000235:genetics* / Q000378:metabolism; D021122:Protein Subunits / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D013385:Succinate Dehydrogenase / Q000235:genetics* / Q000378:metabolism
chemical_list: D009097:Multienzyme Complexes; D009687:Nuclear Proteins; D021122:Protein Subunits; D012333:RNA, Messenger; D010088:Oxidoreductases; D042963:Electron Transport Complex II; D013385:Succinate Dehydrogenase