Genomics and proteomics of nucleomorph-containing algae

阿奇博尔德实验室使用分子生物学和计算方法来研究真核生物（含核）的基因和基因组。我们的工作重点是隐藻和绿藻，两个非常不寻常的藻类群体，通过一个称为“次生内共生”的过程获得光合作用。这发生在当一个吞噬（吃细胞）的真核生物吞噬一个光合真核生物并保留其捕光装置（质体）时，并产生了地球上一些最具生态意义的光养生物。在大多数含有次生质体的藻类中，（例如，在硅藻和海带），次级内共生体的细胞核已经完全消失，将所有必需基因转移到宿主细胞的细胞核基因组中。然而，在隐藻和绿藻中，内共生体的细胞核以称为“核形”的小型化形式存在，并且内共生体衍生的细胞质（“周质空间”）被保留为基本细胞过程如DNA复制、转录和翻译的位点。由于核型基因组的编码能力是非常有限的，大多数蛋白质的功能，在周质体空间必须宿主核编码，但细胞过程的多样性发生在这个不寻常的细胞隔室是目前未知的。使用一组分子，生物化学和比较基因组技术，我们将分析的质体，周质体和核晶蛋白质组的隐藻和绿藻藻，以（1）阐明其真正的生物化学复杂性和（2）了解在何种程度上主机和内共生体衍生的蛋白质有助于分子机器现在在主机和内共生体细胞质室的功能。这项研究将深入了解维持核心真核细胞过程所需的最小分子机制，更普遍的是，揭示了一种内共生过程，这种过程已经在地球上产生了无数种含有次级质体的藻类。

The Archibald Laboratory uses molecular biological and computational methods to study the genes and genomes of eukaryotic (nucleus-containing) organisms. Our work focuses on the cryptophytes and chlorarachniophytes, two highly unusual groups of algae that acquired photosynthesis through a process called 'secondary endosymbiosis'. This occurs when a phagotrophic (cell-eating) eukaryote engulfs a photosynthetic eukaryote and retains its light-harvesting apparatus (plastid), and has given rise to some of the most ecologically significant phototrophs on the planet. In most secondary plastid-containing algae, (e.g., diatoms and kelp), the nucleus of the secondary endosymbiont has completely disappeared, having transferred all essential genes to the nuclear genome of the host cell. However, in cryptophytes and chlorarachniophytes, the endosymbiont nucleus persists in a miniaturized form called a 'nucleomorph', and the endosymbiont-derived cytoplasm (the 'periplasmic space') is retained as the site of essential cellular processes such as DNA replication, transcription and translation. As the coding capacity of nucleomorph genomes is extremely limited, most of the proteins functioning in the periplastid space must be host nucleus-encoded, but the diversity of cellular processes taking place in this unusual cellular compartment are currently unknown. Using a battery of molecular, biochemical and comparative genomic techniques, we will analyze the plastid, periplastid and nucleomorph proteomes of cryptophyte and chlorarachniophyte algae in order to (1) elucidate their true biochemical complexity and (2) understand the extent to which host- and endosymbiont-derived proteins have contributed to the molecular machines now functioning in both the host and endosymbiont cytoplasmic compartments. This research will provide insight into the minimal molecular machinery required to sustain core eukaryotic cellular processes and, more generally, shed light on an endosymbiotic process that has given rise to countless species of secondary plastid-containing algae on Earth.