ISGlobal, Barcelona Ctr. Int. Health Res. (CRESIB), Hospital Clínic - Universitat de Barcelona, Barcelona, Spain.
Parasitology. 2019 Dec;146(14):1767-1772. doi: 10.1017/S0031182019001380. Epub 2019 Oct 23.
C-mannosylation was recently identified in the thrombospondin-related anonymous protein (TRAP) from Plasmodium falciparum salivary gland sporozoites. A candidate P. falciparum C-mannosyltransferase (PfDPY-19) was demonstrated to modify thrombospondin type 1 repeat (TSR) domains in vitro, exhibiting a different acceptor specificity than their mammalian counterparts. According to the described minimal acceptor of PfDPY19, several TSR domain-containing proteins of P. falciparum could be C-mannosylated in vivo. However, the relevance of this protein modification for the parasite viability remains unknown. In the present study, we used CRISPR/Cas9 technology to generate a PfDPY19 null mutant, demonstrating that this glycosyltransferase is not essential for the asexual blood development of the parasite. PfDPY19 gene disruption was not associated with a growth phenotype, not even under endoplasmic reticulum-stressing conditions that could impair protein folding. The data presented in this work strongly suggest that PfDPY19 is unlikely to play a critical role in the asexual blood stages of the parasite, at least under in vitro conditions.
C-甘露糖化作用最近在恶性疟原虫唾液腺孢子虫的血小板反应蛋白相关的匿名蛋白（TRAP）中被鉴定出来。已证明候选的恶性疟原虫 C-甘露糖基转移酶（PfDPY-19）在体外修饰血小板反应蛋白 1 型重复（TSR）结构域，其接受体特异性与哺乳动物的不同。根据 PfDPY19 的描述性最小接受体，恶性疟原虫中的几种含有 TSR 结构域的蛋白可以在体内进行 C-甘露糖化。然而，这种蛋白修饰对寄生虫活力的相关性尚不清楚。在本研究中，我们使用 CRISPR/Cas9 技术生成了 PfDPY19 缺失突变体，证明该糖基转移酶对于寄生虫的无性血液发育不是必需的。PfDPY19 基因缺失与生长表型无关，即使在可能影响蛋白折叠的内质网应激条件下也没有。本工作中提出的资料强烈表明，PfDPY19 不太可能在寄生虫的无性血液阶段发挥关键作用，至少在体外条件下是如此。
