NCA2, a second nuclear gene required for the control of mitochondrial synthesis of subunits 6 and 8 of ATP synthase in Saccharomyces cerevisiae.
Respiratory-competent nuclear mutants have been isolated which presented a cryosensitive phenotype on a non-fermentable carbon source, due to a dysfunction of the mitochondrial F1-Fo ATP synthase. This defect results from an alteration of the mtDNA-encoded protein synthesis level of subunits 6 and 8 of the Fo sector, due to the simultaneous presence of a mutation in two unlinked nuclear genes. These mutations promote a modification of the expression of the cotranscript ATP8-ATP6 (formerly denoted AAP1-OL12): this mRNA undergoes a maturation at a unique site reaching to two cotranscripts of 5.2 and 4.6 kb in length: in the mutant, the relative amount of 5.2 kb cotranscript was greatly lowered. NCA2 was isolated from a wild-type yeast genomic library by genetic complementation. The relative level of the 5.2 kb transcript, as the synthesis of subunits 6 and 8, was partly restored in the transformed strain. A 1848 nucleotide open reading frame was depicted that encoded an amphiphilic protein of 70,816 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. Hybridization analyses indicated that NCA2 is located on chromosome XVI and produces a single 2750 base transcript.
Camougrand
N
N
Institut de Biochimie, Université de Bordeaux II, France.
Pélissier
P
P
Velours
G
G
Guérin
M
M
D000595:Amino Acid Sequence; D002467:Cell Nucleus / Q000378:metabolism; D008928:Mitochondria / Q000378:metabolism*; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000235:genetics* / Q000302:isolation & purification; D006180:Proton-Translocating ATPases / Q000096:biosynthesis*; D012333:RNA, Messenger / Q000032:analysis; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism*
D009687:Nuclear Proteins; D012333:RNA, Messenger; D006180:Proton-Translocating ATPases