Palacpac Nirianne Marie Q, Hiramine Yasushi, Seto Shintaro, Hiramatsu Ryuji, Horii Toshihiro, Mitamura Toshihide
PRESTO, Japan Science and Technology Corporation, 4-1-8 Honcho Kawaguchi, Saitama 332-0012, Japan.
Biochem Biophys Res Commun. 2004 Sep 3;321(4):1062-8. doi: 10.1016/j.bbrc.2004.07.070.
In triacylglycerol (TAG)-accumulating organisms, the physiological roles of diacylglycerol acyltransferase (DGAT), a principal enzyme in the major biosynthetic pathway for TAG, appear to be diverse. Apicomplexan parasite, Plasmodium falciparum, shows unique features in TAG metabolism and trafficking during intraerythrocytic development, and unlike most eukaryotes, only one open reading frame (ORF) encoding a candidate DGAT could be found in its genome. However, whether this candidate ORF encodes P. falciparum DGAT and its physiological relevance have not been assessed. Here, we demonstrate that the ORF is transcribed as a approximately 3.6 kb single mRNA throughout intraerythrocytic development, markedly elevated at trophozoite, schizont, and segmented schizont, and indeed encodes a protein exhibiting DGAT activity. Further, we provide evidence that the parasite in which the ORF was disrupted via double crossover recombination cannot be enriched, implying a fundamental role of PfDGAT in intraerythrocytic proliferation.
在积累三酰甘油（TAG）的生物体中，二酰甘油酰基转移酶（DGAT）作为TAG主要生物合成途径中的一种关键酶，其生理作用似乎多种多样。顶复门寄生虫恶性疟原虫在红细胞内发育过程中的TAG代谢和运输方面表现出独特特征，与大多数真核生物不同，在其基因组中仅能找到一个编码候选DGAT的开放阅读框（ORF）。然而，该候选ORF是否编码恶性疟原虫DGAT及其生理相关性尚未得到评估。在此，我们证明该ORF在整个红细胞内发育过程中转录为约3.6 kb的单一mRNA，在滋养体、裂殖体和分段裂殖体阶段显著升高，并且确实编码一种具有DGAT活性的蛋白质。此外，我们提供的证据表明，通过双交换重组破坏该ORF的寄生虫无法富集，这意味着PfDGAT在红细胞内增殖中具有重要作用。
