Department of Physics, Stanford University, Stanford, CA 94305, USA.
Dipartimento di Biologia, Università degli Studi di Padova, 35122 Padova, Italy; Institute for Stem Cell Biology and Regenerative Medicine, and Ludwig Center, Stanford University School of Medicine, Stanford, CA 94305, USA; Department of Biology, Stanford University, Hopkins Marine Station, Pacific Grove, CA 93950, USA.
Cell Rep. 2021 Jan 26;34(4):108681. doi: 10.1016/j.celrep.2020.108681.
Colonial tunicates are the only chordate that possess two distinct developmental pathways to produce an adult body: either sexually through embryogenesis or asexually through a stem cell-mediated renewal termed blastogenesis. Using the colonial tunicate Botryllus schlosseri, we combine transcriptomics and microscopy to build an atlas of the molecular and morphological signatures at each developmental stage for both pathways. The general molecular profiles of these processes are largely distinct. However, the relative timing of organogenesis and ordering of tissue-specific gene expression are conserved. By comparing the developmental pathways of B. schlosseri with other chordates, we identify hundreds of putative transcription factors with conserved temporal expression. Our findings demonstrate that convergent morphology need not imply convergent molecular mechanisms but that it showcases the importance that tissue-specific stem cells and transcription factors play in producing the same mature body through different pathways.
一种是通过胚胎发生进行有性繁殖，另一种是通过被称为出芽发生的干细胞介导的更新进行无性繁殖。利用殖民被囊动物泡叶藻属，我们结合转录组学和显微镜技术，为这两种途径的每个发育阶段构建了分子和形态特征图谱。这些过程的一般分子特征在很大程度上是不同的。然而，器官发生的相对时间和组织特异性基因表达的顺序是保守的。通过比较泡叶藻属的发育途径与其他脊索动物，我们鉴定出数百种具有保守时间表达的假定转录因子。我们的研究结果表明，趋同的形态不一定意味着趋同的分子机制，但它展示了组织特异性干细胞和转录因子在通过不同途径产生相同成熟身体中的重要作用。
