Dai Yichen, Pan Rongrong, Pan Qi, Wu Xiaotong, Cai Zexin, Fu Yongheng, Shi Chenggang, Sheng Yuyu, Li Jingjing, Lin Zhe, Liu Gaoming, Zhu Pingfen, Li Meng, Li Guang, Zhou Xuming
Key Laboratory of Animal Ecology and Conservation Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China.
State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiangan District, Xiamen, Fujian 361102, China.
Sci Adv. 2024 Dec 20;10(51):eadq0702. doi: 10.1126/sciadv.adq0702.
Despite their pivotal role, the evolutionary origins of vertebrate digestive systems remain enigmatic. We explored the cellular characteristics of the amphioxus () digestive tract, a model for the presumed primitive chordate digestive system, using bulk tissue companioned with single-cell RNA sequencing. Our findings reveal segmentation and a rich diversity of cell clusters, and we highlight the presence of epithelial-like, ciliated cells in the amphioxus midgut and describe three types of endocrine-like cells that secrete insulin-like, glucagon-like, and somatostatin-like peptides. Furthermore, , , , and knockout amphioxus lines revealed that, in amphioxus, does not influence expression. We also unravel similarity between amphioxus Ilp1 and vertebrate insulin-like growth factor 1 (Igf1) in terms of predicted structure, effects on body growth and amino acid metabolism, and interactions with Igf-binding proteins. These findings indicate that the evolutionary alterations involving the regulatory influence of Pdx over gene expression could have been instrumental in the development of the vertebrate digestive system.
尽管脊椎动物消化系统具有关键作用，但其进化起源仍不明晰。我们利用批量组织结合单细胞RNA测序，探索了文昌鱼消化道的细胞特征，文昌鱼消化道被视为原始脊索动物消化系统的模型。我们的研究结果揭示了其节段性和丰富多样的细胞簇，并且我们强调了文昌鱼中肠存在上皮样纤毛细胞，并描述了三种分泌胰岛素样、胰高血糖素样和生长抑素样肽的类内分泌细胞。此外，[具体基因1]、[具体基因2]、[具体基因3]和[具体基因4]敲除的文昌鱼品系显示，在文昌鱼中，[具体基因1]不影响[具体基因2]的表达。我们还揭示了文昌鱼Ilp1与脊椎动物胰岛素样生长因子1（Igf1）在预测结构、对身体生长和氨基酸代谢的影响以及与Igf结合蛋白的相互作用方面的相似性。这些发现表明，涉及Pdx对[具体基因]基因表达调控影响的进化改变可能对脊椎动物消化系统的发育起到了重要作用。
