Retention of transcriptionally active cryptophyte nuclei by the ciliate Myrionecta rubra
Retention of transcriptionally active cryptophyte nuclei by the ciliate Myrionecta rubra
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DOI：
10.1038/nature05496
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发表时间：
2007-01-25
期刊：
影响因子：
64.8
通讯作者：
Stoecker, Diane K.
中科院分区：
文献类型：
--
作者：
Johnson, Matthew D.;Oldach, David;Stoecker, Diane K.
众所周知，细胞器可被捕食性生物保留和利用，但在大多数情况下，这种封存仅限于捕食藻类的质体(1)。此外，猎物细胞器的隔离通常是非常短暂的(2)，因为细胞器在没有参与其调节、分裂和功能的许多核编码基因的情况下无法保持功能(3)。海洋光合纤毛虫Myrionecta rubra(Lohmann 1908)Jankowski 1976(与Mesoddium rubrum相同)(4)具有隐芽起源的细胞器(5-9)，这引发了关于它们是永久共生还是临时隔离固定物的争论(5-13)。最近，红色微囊藻被证明从隐单胞菌中窃取叶绿体(即叶绿体)，并观察到在摄食后猎物核积累。在这里，我们发现红色微囊藻的隐芽核可保留长达30天，是转录活性较高的服务质体，来源于多个隐芽细胞。随着隔离的核从种群中消失，参与质体功能的隐藻核编码基因的表达在红色木霉中下降。胞质分裂、质体的性能和它们的复制依赖于隐芽细胞核的反复窃取。Karyokepty(源于希腊语kerdi，核；kleftis，窃贼)代表了一种以前未知的获得生化潜力的进化策略。
It is well documented that organelles can be retained and used by predatory organisms, but in most cases such sequestrations are limited to plastids of algal prey(1). Furthermore, sequestrations of prey organelles are typically highly ephemeral(2) as a result of the inability of the organelle to remain functional in the absence of numerous nuclear-encoded genes involved in its regulation, division and function(3). The marine photosynthetic ciliate Myrionecta rubra (Lohmann 1908) Jankowski 1976 ( the same as Mesodinium rubrum)(4) is known to possess organelles of cryptophyte origin(5-9), which has led to debate concerning their status as permanent symbiotic or temporary sequestered fixtures(5-13). Recently, M. rubra has been shown to steal plastids ( that is, chloroplasts) from the cryptomonad, Geminigera cryophila, and prey nuclei were observed to accumulate after feeding(10). Here we show that cryptophyte nuclei in M. rubra are retained for up to 30 days, are transcriptionally active and service plastids derived from multiple cryptophyte cells. Expression of a cryptophyte nuclear-encoded gene involved in plastid function declined in M. rubra as the sequestered nuclei disappeared from the population. Cytokinesis, plastid performance and their replication are dependent on recurrent stealing of cryptophyte nuclei. Karyoklepty ( from Greek karydi, kernel; kleftis, thief) represents a previously unknown evolutionary strategy for acquiring biochemical potential.