高等植物质体的分裂

An Emerging Picture of Plastid Division in Higher Plants

质体来源于早期具光合能力的原核生物与原始真核生物的内共生事件。原核起源的蛋白以及真核寄主起源的蛋白共同参与了质体的分裂过程。以原核生物的细胞分裂蛋白为蓝本,近些年在植物中陆续鉴定出几种主要的原核生物细胞分裂蛋白的同源物,如FtsZ、MinD和MinE蛋白。然而,除此之外,原核细胞大多数分裂相关因子在植物中找不到其同源物,但却鉴定了许多真核寄主来源的分裂相关蛋白。当前研究的重点是剖析各种质体分裂蛋白协同作用的机制,业已证明MinD和MinE的协同作用保证了FtsZ(Z)环的正确定位。尽管经典的FtsZ的抑制因子MinC在植物中不存在,但实验表明ARC3在拟南芥中具有类似MinC的功能。ARC3蛋白与真核起源的蛋白如ARC5、ARTEMIS、FZL和PD环以及其它原核起源的蛋白如ARC6和GC1等共同构成了一个复杂的植物质体分裂调控系统。

Plastids are derived from endosymbiotic photosynthetic bacteria, so the division of plastids is controlled by a combination of prokaryote-and host eukaryote-derived proteins. Because of their prokaryotic origin, bacterial cell division has been successfully used as a paradigm for plastid division. This paradigm has resulted in the identification of the key plastid division components FtsZ, MinD, and MinE. However, most bacterial division factors are absent from chloroplasts, and the eukaryotic host has added several new components. Current research explores how these plastid division-related proteins interact with each other. FtsZ initiates plastid division, whereas the coordinated action of MinD and MinE ensures correct FtsZ （Z）-ring placement. Although the classical FtsZ antagonist MinC does not exist in plants, ARC3 can fulfill this role in Arabidopsis. Together with eukaryotic-derived proteins such as ARC5, ARTEMIS, PD rings and FZL and other prokaryotic-derived proteins such as ARC6 and GC1, these proteins make up a sophisticated division machinery in higher plants.