PNAS:用于疟蚊控制的基因驱动

摘要 : 美国加州大学欧文分校科研人员报告了一种基于CRISPR/Cas9的基因驱动系统原型，用于改造蚊子对疟疾寄生虫的耐性。

美国加州大学欧文分校科研人员报告了一种基于CRISPR/Cas9的基因驱动系统原型，用于改造蚊子对疟疾寄生虫的耐性。在全世界范围，仅2014年就有58万人死于疟疾。为了让针对疟疾寄生虫的耐性在蚊子病媒中扩散，Anthony James及其同事制造了一个基于CRISPR/Cas9的基因驱动系统，它能够把一种抗寄生虫基因引入到蚊子中间并加以扩散。在一个使用斯氏按蚊(Anopheles stephensi)这种造成了印度估计约12%的疟疾传播的蚊子的概念验证研究中，这组作者证明了一种经过改造的基因驱动系统能够在蚊子中间传播一种双重抗寄生虫效应子基因。这种抗寄生虫基因针对人类疟疾寄生虫恶性疟原虫(Plasmodium falciparum)的感染阶段制造的两种关键蛋白质，在一个高度特异性的基因转换事件中在雄性和雌性蚊子种系里扩散，效率大于98%。这个17千碱基结构的遗传载荷在目标蚊子以血为食的时候触发。这组作者还发现了一种对Cas9表达的抑制驱动的母系效应，必须克服这种效应从而优化这种驱动在野外的使用。尽管这些发现带来了朝着蚊子种群修饰的有希望的一步，需要进行效应子基因在不同的蚊子类型和环境条件下的稳定性的研究，从而验证这种控制疟疾的驱动系统。这组作者说，在这个基因驱动系统在实地环境中有适当的社会接受和监管的情况下，这种方法可能代表了不断增长的抗疟疾武库中的一个强有力的武器。

原文链接：

Highly efficient Cas9-mediated GENE drive for population modification of the malaria vector mosquito Anopheles stephensi

原文摘要：

genetic engineering technologies can be used both to create transgenic mosquitoes carrying antipathogen effector genes targeting human malaria parasites and to generate gene-drive systems capable of introgressing the genes throughout wild vector populations. We developed a highly effective autonomous Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)-associated protein 9 (Cas9)-mediated gene-drive system in the Asian malaria vector Anopheles stephensi, adapted from the mutagenic chain reaction (MCR). This specific system results in progeny of males and females derived from transgenic males exhibiting a high frequency of germ-line gene conversion consistent with homology-directed repair (HDR). This system copies an ∼17-kb construct from its site of insertion to its homologous chromosome in a faithful, site-specific manner. Dual anti-Plasmodium falciparum effector genes, a marker gene, and the autonomous gene-drive components are introgressed into ∼99.5% of the progeny following outcrosses of transgenic lines to wild-type mosquitoes. The effector genes remain transcriptionally inducible upon blood feeding. In contrast to the efficient conversion in individuals expressing Cas9 only in the germ line, males and females derived from transgenic females, which are expected to have drive component molecules in the egg, produce progeny with a high frequency of mutations in the targeted genome sequence, resulting in near-Mendelian inheritance ratios of the transgene. Such mutant alleles result presumably from nonhomologous end-joining (NHEJ) events before the segregation of somatic and germ-line lineages early in development. These data support the design of this system to be active strictly within the germ line. Strains based on this technology could sustain control and elimination as part of the malaria eradication agenda.

doi: 10.1073/PNAS.1521077112

作者：Valentino Gantz

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