台湾中央研究院Chen-Hui Chen团队近期取得重要工作进展，他们研究发现斑马鱼的皮肤细胞经历了“合成裂变”以扩大体表，该项研究成果2022年4月27日在线发表于《自然》杂志上。

在这里，研究人员创建了一个多色细胞膜标记系统，palmskin，以监测发育中的斑马鱼幼虫的整个浅表上皮细胞 (SECs) 群。使用延时成像，他们发现许多SECs很容易在动物体表分裂。在特定的发育窗口期间，单个SEC在其生命周期内可以在动物表面产生最多四个子代细胞。值得注意的是，EdU分析、DNA染色和羟基脲处理表明，尽管没有DNA复制，这些终末分化的皮肤细胞仍在继续分裂，导致多达50%的SEC表现出基因组大小减小。在简单的数学模型和细胞体积和顶端表面积的定量分析的基础上，研究人员提出“合成裂变”是快速生长过程中扩大上皮覆盖率的有效机制。

此外，体表生长的全局或局部操作会影响SEC分裂的程度和模式，可能是通过张力介导的拉伸激活离子通道的激活影响的。研究人员推测，这种节俭而灵活的细胞增殖模式也可能发生在斑马鱼皮肤扩张以外的环境中。

据了解，当动物的表面积在发育过程中扩大时，皮肤细胞群会迅速作出反应，以维持足够的上皮覆盖。尽管在对活体皮肤细胞行为的理解上取得了很大进展，但尚不清楚细胞如何在生物体水平上集体行动以满足覆盖率需求。

附：英文原文

Title: Skin cells undergo asynthetic fission to expand body surfaces in zebrafish

Author: Chan, Keat Ying, Yan, Ching-Cher Sanders, Roan, Hsiao-Yuh, Hsu, Shao-Chun, Tseng, Tzu-Lun, Hsiao, Chung-Der, Hsu, Chao-Ping, Chen, Chen-Hui

Issue&Volume: 2022-04-27

Abstract: As an animal’s surface area expands during development, skin cell populations must quickly respond to maintain sufficient epithelial coverage. Despite much progress in understanding of skin cell behaviours in vivo1,2, it remains unclear how cells collectively act to satisfy coverage demands at an organismic level. Here we created a multicolour cell membrane tagging system, palmskin, to monitor the entire population of superficial epithelial cells (SECs) in developing zebrafish larvae. Using time-lapse imaging, we found that many SECs readily divide on the animal body surface; during a specific developmental window, a single SEC can produce a maximum of four progeny cells over its lifetime on the surface of the animal. Remarkably, EdU assays, DNA staining and hydroxyurea treatment showed that these terminally differentiated skin cells continue splitting despite an absence of DNA replication, causing up to 50% of SECs to exhibit reduced genome size. On the basis of a simple mathematical model and quantitative analyses of cell volumes and apical surface areas, we propose that ‘asynthetic fission’ is used as an efficient mechanism for expanding epithelial coverage during rapid growth. Furthermore, global or local manipulation of body surface growth affects the extent and mode of SEC division, presumably through tension-mediated activation of stretch-activated ion channels. We speculate that this frugal yet flexible mode of cell proliferation might also occur in contexts other than zebrafish skin expansion.

DOI: 10.1038/s41586-022-04641-0

Source: https://www.nature.com/articles/s41586-022-04641-0