Viola A M, Lodi T, Ferrero I
Institute of Genetics, University of Parma, Parco Area delle Scienze 11/A, I-43100 Parma, Italy.
Curr Genet. 1999 Aug;36(1-2):29-36. doi: 10.1007/s002940050469.
The KlAAC gene, encoding the ADP/ATP carrier in Kluveromyces lactis, has previously been cloned by complementation of the op1(aac2) mutation of Saccharomyces cerevisiae. We examined the effect of a null mutation of this gene on the phenotype of K. lactis. The consequence of this mutation was found to be multiple. The mutant was respiratory deficient, had an undetectable level of cytochrome a-a3 and b and did not grow on glycerol. The mitochondrial D-lactate ferricytochrome c oxidoreductase activity, as well as the lactate-induced transcription of its gene, KlDLD, was severely reduced. Furthermore, the mutant was unable to grow on galactose, maltose and raffinose. Transcript analysis showed that KlAAC was the only ADP/ATP carrier gene present in K. lactis. The Klaac mutation was fully complemented not only by AAC2, the major gene for the ADP/ATP carrier in S. cerevisiae, but also by AAC1, a gene which is poorly expressed in S. cerevisiae. AAC1 introduced in K. lactis was transcribed to a high level consistent with normal growth on glycerol being restored in the transformed mutant. KlAAC was not subject to control by KlHap2, in contrast to AAC2 which is regulated by the Hap2 complex in S. cerevisiae.
编码乳酸克鲁维酵母中ADP/ATP载体的KlAAC基因，先前已通过互补酿酒酵母的op1(aac2)突变进行克隆。我们研究了该基因的无效突变对乳酸克鲁维酵母表型的影响。发现这种突变的后果是多方面的。突变体呼吸缺陷，细胞色素a-a3和b水平检测不到，且不能在甘油上生长。线粒体D-乳酸铁细胞色素c氧化还原酶活性及其基因KlDLD的乳酸诱导转录均严重降低。此外，突变体不能在半乳糖、麦芽糖和棉子糖上生长。转录分析表明，KlAAC是乳酸克鲁维酵母中唯一存在的ADP/ATP载体基因。Klaac突变不仅被酿酒酵母中ADP/ATP载体的主要基因AAC2完全互补，还被酿酒酵母中表达水平较低的基因AAC1完全互补。导入乳酸克鲁维酵母中的AAC1转录水平很高，这与转化突变体中甘油上的正常生长恢复一致。与酿酒酵母中受Hap2复合体调控的AAC2不同，KlAAC不受KlHap2的调控。
