The circumsporozoite protein, CSP is the major surface protein of Plasmodium sporozoites, the form of malaria parasites transmitted by mosquitoes. CSP is involved in sporozoite formation within and egress from oocysts, entry into mosquito salivary glands and mammalian liver as well as migration in the skin. Antibodies against CSP can stop infection prior to the first round of parasite replication in the liver. CSP consists of different domains and is proteolytically cleaved prior to hepatocyte invasion. Part of CSP has been developed into a licensed vaccine against malaria. Yet, how CSP facilitates sporozoite formation, oocyst egress and hepatocyte specific invasion is still not fully understood. Here, we generated a series of parasites expressing full-length versions of CSP as fusion proteins with the green fluorescent protein. This enabled the investigation of sporozoite formation in living oocysts and revealed a dominant negative function of some GFP-CSP fusions during sporozoite egress.

中文翻译：

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疟原虫环子孢子蛋白的荧光标记允许子孢子形成的成像，但阻止卵囊的流出

环子孢子蛋白（CSP）是疟原虫子孢子的主要表面蛋白，是蚊子传播的疟原虫的形式。CSP参与卵囊内部和卵囊中的子孢子形成，进入蚊唾液腺和哺乳动物肝脏以及在皮肤中迁移。针对CSP的抗体可以在肝脏中第一轮寄生虫复制之前停止感染。CSP由不同的域组成，并在肝细胞入侵之前被蛋白水解切割。CSP的一部分已发展成为一种许可的抗疟疾疫苗。但是，CSP如何促进子孢子的形成，卵囊的排出和肝细胞特异性的侵袭尚不完全清楚。在这里，我们生成了一系列寄生虫，这些寄生虫将CSP的全长版本表达为绿色荧光蛋白与融合蛋白。