Expression level of methanol-inducible peroxisomal proteins is affected by oxygen conditions and mitochondrial respiratory pathway function in the methylotrophic yeast

甲醇营养酵母除了作为线粒体呼吸链的末端电子受体外，还需要氧气来完成过氧化体内AOD催化的甲醇代谢反应。因此，酵母细胞必须有一种控制甲醇代谢的机制，该机制对氧气水平做出反应，以平衡这两个细胞器之间的氧气需求。在这项研究中，我们发现只有在有氧条件下才能诱导甲醇诱导的过氧体蛋白，并且这些基因的表达通过抑制线粒体呼吸链而受到抑制。在呼吸缺陷突变株中，尽管有氧气存在，它们的诱导水平仍然很低。综上所述，这些事实表明，酵母能够感知氧气条件，线粒体的呼吸功能可能对甲醇诱导的过氧化体蛋白基因表达具有深远的影响。

Oxygen is required by methylotrophic yeast for the AOD-catalyzed reactions within peroxisomes for methanol metabolism in addition to its role as the terminal electron acceptor for the respiratory chain in the mitochondria. Therefore, the yeast cells must have a mechanism for controlling the methanol metabolism, which responds to oxygen levels, in order to balance the oxygen needs between these two organelles. In this study we showed that methanol-inducible peroxisomal proteins were induced only under aerobic conditions, and those gene expression was repressed by inhibition of the mitochondrial respiratory chain. In the respiratory deficient mutant strains, their induction was at very low levels despite the presence of oxygen. Taken together, these facts indicate that the yeast can sense oxygen conditions, and that mitochondrial respiratory function may have a profound effect on induction of methanol-inducible gene expression of peroxisomal proteins.