Sakai Y, Nakagawa T, Shimase M, Kato N
Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kitashirakawa-Oiwake, Sakyo-ku, Kyoto 606-8502, Japan.
J Bacteriol. 1998 Nov;180(22):5885-90. doi: 10.1128/JB.180.22.5885-5890.1998.
The physiological role of dihydroxyacetone synthase (DHAS) in Candida boidinii was evaluated at the molecular level. The DAS1 gene, encoding DHAS, was cloned from the host genome, and regulation of its expression by various carbon and nitrogen sources was analyzed. Western and Northern analyses revealed that DAS1 expression was regulated mainly at the mRNA level. The regulatory pattern of DHAS was similar to that of alcohol oxidase but distinct from that of two other enzymes in the formaldehyde dissimilation pathway, glutathione-dependent formaldehyde dehydrogenase and formate dehydrogenase. The DAS1 gene was disrupted in one step in the host genome (das1Delta strain), and the growth of the das1Delta strain in various carbon and nitrogen sources was compared with that of the wild-type strain. The das1Delta strain had completely lost the ability to grow on methanol, while the strain with a disruption of the formate dehydrogenase gene could survive (Y. Sakai et al., J. Bacteriol. 179:4480-4485, 1997). These and other experiments (e.g., those to determine the expression of the gene and the growth ability of the das1Delta strain on media containing methylamine or choline as a nitrogen source) suggested that DAS1 is involved in assimilation rather than dissimilation or detoxification of formaldehyde in the cells.
在分子水平上评估了二羟基丙酮合酶（DHAS）在博伊丁假丝酵母中的生理作用。从宿主基因组中克隆了编码DHAS的DAS1基因，并分析了其在各种碳源和氮源作用下的表达调控情况。蛋白质免疫印迹和Northern印迹分析表明，DAS1的表达主要在mRNA水平受到调控。DHAS的调控模式与乙醇氧化酶相似，但与甲醛异化途径中的其他两种酶，即谷胱甘肽依赖性甲醛脱氢酶和甲酸脱氢酶不同。在宿主基因组中一步破坏DAS1基因（das1Delta菌株），并将das1Delta菌株在各种碳源和氮源中的生长情况与野生型菌株进行比较。das1Delta菌株完全丧失了在甲醇上生长的能力，而甲酸脱氢酶基因被破坏的菌株能够存活（Y. Sakai等人，《细菌学杂志》179:4480 - 4485，1997）。这些以及其他实验（例如，确定该基因的表达以及das1Delta菌株在以甲胺或胆碱作为氮源的培养基上的生长能力的实验）表明，DAS1参与细胞中甲醛的同化作用，而非异化作用或解毒作用。
