Triplicate genes for mitochondrial ADP/ATP carriers in the aerobic yeast Yarrowia lipolytica are regulated differentially in the absence of oxygen.
Yarrowia lipolytica is a strictly aerobic fungus, which differs from the extensively studied model yeasts Saccharomyces cerevisiae and Schizosaccharomyces pombe with respect to its physiology, genetics and dimorphic growth habit. We isolated and sequenced cDNA and genomic clones (YlAAC1) from Y. lipolytica that encode a mitochondrial ADP/ATP carrier. The YlAAC1 gene can complement the S. cerevisiae Deltaaac2 deletion mutant. Southern hybridization, analysis of Yarrowia clones obtained in the course of the Genolevures project, and further sequencing revealed the existence of two paralogs of the YlAAC1 gene, which were named YlAAC2 and YlAAC3, respectively. Phylogenetic analysis showed that YlAAC1 and YlAAC2 were more closely related to each other than to YlAAC3, and are likely to represent the products of a recent gene duplication. All three Y. lipolytica YlAAC genes group together on the phylogenetic tree, suggesting that YlAAC3 is derived from a more ancient duplication within the Y. lipolytica lineage. A similar branching pattern for the three ScAAC paralogs in the facultative anaerobe S. cerevisiae demonstrates that two rounds of duplication of AAC genes occurred independently at least twice in the evolution of hemiascomycetous yeasts. Surprisingly, in both the aerobic Y. lipolytica and the facultative anaerobe S. cerevisiae, the three paralogs are differentially regulated in the absence of oxygen. Apparently, Y. lipolytica can sense hypoxia and down-regulate target genes in response.
Mentel
Marek
M
Department of Biochemistry, Faculty of Natural Sciences, Comenius University, Mlynska dolina CH-I, 842 15 Bratislava, Slovakia.
Piskur
Jure
J
Neuvéglise
Cécile
C
Rycovská
Adriana
A
Cellengová
Gabriela
G
Kolarov
Jordan
J
D000595:Amino Acid Sequence; D001483:Base Sequence; D015139:Blotting, Southern; D016000:Cluster Analysis; D018076:DNA, Complementary / Q000235:genetics; D015966:Gene Expression Regulation, Fungal / Q000502:physiology*; D000226:Mitochondrial ADP, ATP Translocases / Q000235:genetics*; D008969:Molecular Sequence Data; D005810:Multigene Family / Q000235:genetics*; D009841:Oligonucleotides; D010100:Oxygen / Q000378:metabolism*; D010802:Phylogeny; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D025062:Yarrowia / Q000235:genetics*
D018076:DNA, Complementary; D009841:Oligonucleotides; D000226:Mitochondrial ADP, ATP Translocases; D010100:Oxygen