NCA3, a nuclear gene involved in the mitochondrial expression of subunits 6 and 8 of the Fo-F1 ATP synthase of S. cerevisiae.
Respiratory-competent nuclear mutants have been isolated which presented a cryosensitive phenotype on a non-fermentative carbon source, due to a dysfunctioning of the mitochondrial F1-Fo ATP synthase which results from a relative defect in subunits 6 and 8 of the Fo sector. Both proteins are mtDNA-encoded, but the defect is due to the simultaneous presence of a mutation in two unlinked nuclear genes (NCA2 and NCA3, for Nuclear Control of ATPase) promoting a modification of the expression of the ATP8-ATP6 co-transcript (formerly denoted AAP1-OLI2). This co-transcript matures at a unique site to give two cotranscripts of 5.2 and 4.6 kb in length: in the mutant, the 5.2-kb co-transcript was greatly lowered. NCA3 was isolated from a wild-type yeast genomic library by genetic complementation. The level of the 5.2-kb transcript, like the synthesis of subunits 6 and 8, was partly restored in the transformed strain. A 1011-nucleotide ORF was identified that encodes an hydrophilic protein of 35417 Da. Disruption of chromosomal DNA within the reading frame promoted a dramatic decrease of the 5.2-kb mRNA but did not abolish the respiratory competence of a wild-type strain. NCA3 is located on chromosome IV and produces a single 1780-b transcript.
Pélissier
P
P
Institut de Biochimie et Génétique Cellulaires, Université de Bordeaux II, France.
Camougrand
N
N
Velours
G
G
Guérin
M
M
D000595:Amino Acid Sequence; D001483:Base Sequence; D002874:Chromosome Mapping; D003001:Cloning, Molecular; D005800:Genes, Fungal; D008928:Mitochondria / Q000201:enzymology* / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D009154:Mutation; D014176:Protein Biosynthesis; D006180:Proton-Translocating ATPases / Q000235:genetics*; D012333:RNA, Messenger; D012441:Saccharomyces cerevisiae / Q000201:enzymology* / Q000235:genetics*; D017422:Sequence Analysis, DNA; D014158:Transcription, Genetic
D012333:RNA, Messenger; D006180:Proton-Translocating ATPases