de Mendoza Alex, Suga Hiroshi, Permanyer Jon, Irimia Manuel, Ruiz-Trillo Iñaki
Institut de Biologia Evolutiva, Universitat Pompeu Fabra, Barcelona, Spain.
Prefectural University of Hiroshima, Shobara, Japan.
Elife. 2015 Oct 14;4:e08904. doi: 10.7554/eLife.08904.
Cell-type specification through differential genome regulation is a hallmark of complex multicellularity. However, it remains unclear how this process evolved during the transition from unicellular to multicellular organisms. To address this question, we investigated transcriptional dynamics in the ichthyosporean Creolimax fragrantissima, a relative of animals that undergoes coenocytic development. We find that Creolimax utilizes dynamic regulation of alternative splicing, long inter-genic non-coding RNAs and co-regulated gene modules associated with animal multicellularity in a cell-type specific manner. Moreover, our study suggests that the different cell types of the three closest animal relatives (ichthyosporeans, filastereans and choanoflagellates) are the product of lineage-specific innovations. Additionally, a proteomic survey of the secretome reveals adaptations to a fungal-like lifestyle. In summary, the diversity of cell types among protistan relatives of animals and their complex genome regulation demonstrates that the last unicellular ancestor of animals was already capable of elaborate specification of cell types.
通过差异基因组调控实现细胞类型特化是复杂多细胞生物的一个标志。然而，在从单细胞生物向多细胞生物过渡的过程中，这一过程是如何演化的仍不清楚。为了解决这个问题，我们研究了鱼孢菌（Creolimax fragrantissima）的转录动态，鱼孢菌是动物的近亲，经历多核体发育。我们发现，鱼孢菌以细胞类型特异性的方式利用可变剪接、长基因间非编码RNA以及与动物多细胞性相关的共调控基因模块的动态调控。此外，我们的研究表明，三种最接近动物的近亲（鱼孢菌、丝盘虫和领鞭毛虫）的不同细胞类型是谱系特异性创新的产物。此外，对分泌蛋白组的蛋白质组学调查揭示了对类似真菌生活方式的适应性。总之，动物原生生物亲属之间细胞类型的多样性及其复杂的基因组调控表明，动物的最后一个单细胞祖先已经能够精细地指定细胞类型。
