Isoprenoid synthesis provides a diverse class of biomolecules including sterols, dolichols, ubiquinones and prenyl groups. The enzyme farnesyl pyrophosphate synthase (FPPS) catalyzes the formation of farnesyl pyrophosphate, a key intermediate for the biosynthesis of all isoprenoids. In Leishmania, FPPS is considered the main target of nitrogen containing bisphosphonates, yet the essentiality of this enzyme remains untested. Using a facilitated knockout approach, we carried out the genetic analysis of FPPS in Leishmania major. Our data indicated that chromosomal null mutants for FPPS could only be generated in presence of an episomally expressed FPPS. Long-term retention of the episome by the chromosomal FPPS-null mutants in culture and in infected BALB/c mice suggests that FPPS is indispensable.

In addition, applying negative selection pressure failed to induce the loss of ectopic FPPS in the chromosomal FPPS-null mutants, although it led to significant growth delay in culture and in mice. Together, our findings have confirmed the essentiality of FPPS in both promastigotes and amastigotes in L. major and thus validate its potential as a drug target for the treatment of cutaneous leishmaniasis.

类异戊二烯合成提供了多种生物分子，包括固醇，三元醇，泛醌和异戊二烯基。法呢基焦磷酸合酶（FPPS）催化法呢基焦磷酸的形成，这是所有类异戊二烯生物合成的关键中间体。在利什曼原虫中，FPPS被认为是含氮双膦酸盐的主要靶标，但该酶的必要性仍未经测试。使用便利的基因敲除方法，我们在利什曼原虫中进行了FPPS的遗传分析。我们的数据表明，FPPS的染色体无效突变体只能在游离表达的FPPS的存在下产生。染色体FPPS可长期保留附加体-null突变体在文化和感染的BALB / c小鼠中提示FPPS是必不可少的。

另外，施加负选择压力不能诱导染色体FPPS- null突变体中异位FPPS的损失，尽管它导致了培养物和小鼠中显着的生长延迟。总之，我们的研究结果已经证实的FPP在两个前鞭毛体和无鞭毛体的必要性利什曼原虫，从而验证其作为药物靶标皮肤利什曼病的治疗潜力。