Levin Tera C, Greaney Allison J, Wetzel Laura, King Nicole
Department of Molecular and Cell Biology, Howard Hughes Medical Institute, University of California, Berkeley, Berkeley, United States.
Elife. 2014 Oct 9;3:e04070. doi: 10.7554/eLife.04070.
The origin of animal multicellularity may be reconstructed by comparing animals with one of their closest living relatives, the choanoflagellate Salpingoeca rosetta. Just as animals develop from a single cell-the zygote-multicellular rosettes of S. rosetta develop from a founding cell. To investigate rosette development, we established forward genetics in S. rosetta. We find that the rosette defect of one mutant, named Rosetteless, maps to a predicted C-type lectin, a class of signaling and adhesion genes required for the development and innate immunity in animals. Rosetteless protein is essential for rosette development and forms an extracellular layer that coats and connects the basal poles of each cell in rosettes. This study provides the first link between genotype and phenotype in choanoflagellates and raises the possibility that a protein with C-type lectin-like domains regulated development in the last common ancestor of choanoflagellates and animals.
通过将动物与其现存的近亲之一——领鞭毛虫玫瑰旋轮虫进行比较，可以重建动物多细胞性的起源。正如动物从单个细胞——受精卵发育而来一样，玫瑰旋轮虫的多细胞玫瑰花结是从一个起始细胞发育而来的。为了研究玫瑰花结的发育，我们在玫瑰旋轮虫中建立了正向遗传学。我们发现，一个名为“无玫瑰”的突变体的玫瑰花结缺陷定位到一个预测的C型凝集素上，C型凝集素是一类动物发育和先天免疫所需的信号传导和粘附基因。“无玫瑰”蛋白对玫瑰花结的发育至关重要，并形成一个细胞外层，覆盖并连接玫瑰花结中每个细胞的基极。这项研究提供了领鞭毛虫基因型与表型之间的首个联系，并提出了一种可能性，即具有C型凝集素样结构域的蛋白质在领鞭毛虫和动物的最后一个共同祖先中调节发育。
