Plasmodium P-Type Cyclin CYC3 Modulates Endomitotic Growth during Oocyst Development in Mosquitoes.
Plasmodium P-Type Cyclin CYC3 Modulates Endomitotic Growth during Oocyst Development in Mosquitoes.
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DOI：
10.1371/journal.ppat.1005273
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发表时间：
2015-11
期刊：
影响因子：
6.7
通讯作者：
Tewari R
中科院分区：
文献类型：
--
作者：
Roques M;Wall RJ;Douglass AP;Ramaprasad A;Ferguson DJ;Kaindama ML;Brusini L;Joshi N;Rchiad Z;Brady D;Guttery DS;Wheatley SP;Yamano H;Holder AA;Pain A;Wickstead B;Tewari R
真核生物中的细胞周期进程和细胞分裂部分由细胞周期蛋白家族及其对细胞周期蛋白依赖性激酶（CDK）的调节所控制。细胞周期蛋白在酵母和人类细胞等模型系统中得到了很好的表征，但令人惊讶的是，人们对它们在疟原虫（导致疟疾的单细胞原生动物寄生虫）中的数量和作用知之甚少。疟原虫的细胞分裂和增殖与许多真核生物不同。在其生命周期中，它经历两种类型的有丝分裂：无性阶段的内有丝分裂和雄性配子发生期间的极快速的有丝分裂过程。宿主肝脏和红细胞中的裂殖生殖（产生裂殖子）和蚊子载体中的孢子生殖（产生孢子）都是在细胞分裂前进行的核内有丝分裂，具有重复的核复制，没有染色体凝聚。特异性细胞周期蛋白在疟原虫细胞增殖过程中的作用尚不清楚。我们在这里显示，疟原虫基因组只包含三个细胞周期蛋白基因，代表一个不寻常的剧目的细胞周期蛋白类。表达和反向遗传分析的单一植物（P）型细胞周期蛋白，CYC3，在啮齿类疟疾寄生虫，伯氏疟原虫，揭示了GFP标记的蛋白质的细胞质和细胞核的位置在整个生命周期。cyc3基因的缺失导致卵囊的大小、数量和生长缺陷，出芽和子孢子形成异常。此外，在配子母细胞和动合子阶段的cyc3缺失和野生型寄生虫的全球转录分析确定了信号传导，入侵和卵囊发育所需的差异表达的基因。总的来说，这些数据表明，cyc3调节伯氏疟原虫卵囊内有丝分裂的发展。疟疾寄生虫是一种单细胞生物体，在脊椎动物宿主和蚊子媒介中以非典型的方式无性繁殖。在蚊子中肠中，卵囊中发生非典型细胞分裂，其中重复的核分裂（内有丝分裂）先于细胞分裂，然后在称为孢子生殖的过程中产生许多子孢子。控制这一过程的分子机制知之甚少。在包括小鼠和酵母细胞在内的许多模式生物中，细胞周期受到细胞周期蛋白家族成员的调节，但该家族在疟原虫中的作用尚不清楚。在这里，我们发现，只有三个细胞周期蛋白基因，并调查的功能，单一的P型细胞周期蛋白（CYC3）在啮齿类疟原虫，伯氏疟原虫。我们发现，CYC3具有细胞质和核定位在整个大部分的寄生虫的生命周期和基因缺失，我们证明CYC3是重要的正常卵囊发育，成熟和子孢子形成。此外，我们发现cyc3的缺失会影响细胞信号传导和卵囊发育所需基因的转录。这些数据表明，CYC3调节卵囊中的无性繁殖，并在蚊子体内的寄生虫发育中起着至关重要的作用。
Cell-cycle progression and cell division in eukaryotes are governed in part by the cyclin family and their regulation of cyclin-dependent kinases (CDKs). Cyclins are very well characterised in model systems such as yeast and human cells, but surprisingly little is known about their number and role in Plasmodium, the unicellular protozoan parasite that causes malaria. Malaria parasite cell division and proliferation differs from that of many eukaryotes. During its life cycle it undergoes two types of mitosis: endomitosis in asexual stages and an extremely rapid mitotic process during male gametogenesis. Both schizogony (producing merozoites) in host liver and red blood cells, and sporogony (producing sporozoites) in the mosquito vector, are endomitotic with repeated nuclear replication, without chromosome condensation, before cell division. The role of specific cyclins during Plasmodium cell proliferation was unknown. We show here that the Plasmodium genome contains only three cyclin genes, representing an unusual repertoire of cyclin classes. Expression and reverse genetic analyses of the single Plant (P)-type cyclin, CYC3, in the rodent malaria parasite, Plasmodium berghei, revealed a cytoplasmic and nuclear location of the GFP-tagged protein throughout the lifecycle. Deletion of cyc3 resulted in defects in size, number and growth of oocysts, with abnormalities in budding and sporozoite formation. Furthermore, global transcript analysis of the cyc3-deleted and wild type parasites at gametocyte and ookinete stages identified differentially expressed genes required for signalling, invasion and oocyst development. Collectively these data suggest that cyc3 modulates oocyst endomitotic development in Plasmodium berghei. The malaria parasite is a single-celled organism that multiplies asexually in a non-canonical way in both vertebrate host and mosquito vector. In the mosquito midgut, atypical cell division occurs in oocysts, where repeated nuclear division (endomitosis) precedes cell division, which then gives rise to many sporozoites in a process known as sporogony. The molecular mechanisms controlling this process are poorly understood. In many model organisms including mouse and yeast cells the cell cycle is regulated by members of the cyclin protein family, but the role of this family in the malaria parasite is unknown. Here, we show that there are only three cyclin genes and investigate the function of the single P-type cyclin (CYC3) in the rodent malaria parasite, Plasmodium berghei. We show that CYC3 has a cytoplasmic and nuclear localisation throughout most of the parasite lifecycle and by gene deletion we demonstrate that CYC3 is important for normal oocyst development, maturation and sporozoite formation. Moreover, we show that deletion of cyc3 affects the transcription of genes required for cell signalling and oocyst development. The data suggest that CYC3 modulates asexual multiplication in oocysts and plays a vital role in parasite development in the mosquito.