Protistology and Aquatic Ecology, Department of Biology, Ghent University, Krijgslaan 281-S8, 9000 Gent, Belgium.
Genome Biol. 2010;11(2):R17. doi: 10.1186/gb-2010-11-2-r17. Epub 2010 Feb 8.
Despite the enormous importance of diatoms in aquatic ecosystems and their broad industrial potential, little is known about their life cycle control. Diatoms typically inhabit rapidly changing and unstable environments, suggesting that cell cycle regulation in diatoms must have evolved to adequately integrate various environmental signals. The recent genome sequencing of Thalassiosira pseudonana and Phaeodactylum tricornutum allows us to explore the molecular conservation of cell cycle regulation in diatoms.
By profile-based annotation of cell cycle genes, counterparts of conserved as well as new regulators were identified in T. pseudonana and P. tricornutum. In particular, the cyclin gene family was found to be expanded extensively compared to that of other eukaryotes and a novel type of cyclins was discovered, the diatom-specific cyclins. We established a synchronization method for P. tricornutum that enabled assignment of the different annotated genes to specific cell cycle phase transitions. The diatom-specific cyclins are predominantly expressed at the G1-to-S transition and some respond to phosphate availability, hinting at a role in connecting cell division to environmental stimuli.
The discovery of highly conserved and new cell cycle regulators suggests the evolution of unique control mechanisms for diatom cell division, probably contributing to their ability to adapt and survive under highly fluctuating environmental conditions.
尽管硅藻在水生生态系统中具有巨大的重要性及其广泛的工业潜力，但对其生命周期调控知之甚少。硅藻通常栖息在快速变化和不稳定的环境中，这表明硅藻的细胞周期调控必须进化以充分整合各种环境信号。最近对 Thalassiosira pseudonana 和 Phaeodactylum tricornutum 的基因组测序使我们能够探索硅藻细胞周期调控的分子保守性。
通过基于轮廓的细胞周期基因注释，在 T. pseudonana 和 P. tricornutum 中鉴定出保守和新的调节剂的对应物。特别是，与其他真核生物相比，细胞周期基因家族得到了广泛扩展，并发现了一种新型的细胞周期蛋白，即硅藻特异性细胞周期蛋白。我们建立了一种用于 P. tricornutum 的同步方法，使不同注释基因能够分配到特定的细胞周期相位转变。硅藻特异性细胞周期蛋白主要在 G1 到 S 期表达，并且一些对磷酸盐可用性有反应，暗示它们在将细胞分裂与环境刺激联系起来方面发挥作用。
高度保守和新的细胞周期调节剂的发现表明，硅藻细胞分裂的独特控制机制的进化可能有助于它们在高度波动的环境条件下适应和生存的能力。
