Saavedra Pedro, Vincent Jean-Paul, Palacios Isabel M, Lawrence Peter A, Casal José
Department of Zoology, University of Cambridge, Cambridge, United Kingdom.
Elife. 2014 Feb 11;3:e01569. doi: 10.7554/eLife.01569.
Drosophila has helped us understand the genetic mechanisms of pattern formation. Particularly useful have been those organs in which different cell identities and polarities are displayed cell by cell in the cuticle and epidermis (Lawrence, 1992; Bejsovec and Wieschaus, 1993; Freeman, 1997). Here we use the pattern of larval denticles and muscle attachments and ask how this pattern is maintained and renewed over the larval moult cycles. During larval growth each epidermal cell increases manyfold in size but neither divides nor dies. We follow individuals from moult to moult, tracking marked cells and find that, as cells are repositioned and alter their neighbours, their identities change to compensate and the pattern is conserved. Single cells adopting a new fate may even acquire a new polarity: an identified cell that makes a forward-pointing denticle in the first larval stage may make a backward-pointing denticle in the second and third larval stages. DOI: http://dx.doi.org/10.7554/eLife.01569.001.
果蝇帮助我们理解了模式形成的遗传机制。特别有用的是那些在表皮和角质层中逐个细胞地展示出不同细胞身份和极性的器官（劳伦斯，1992年；贝乔维克和维绍斯，1993年；弗里曼，1997年）。在这里，我们利用幼虫体节和肌肉附着的模式，探究这种模式在幼虫蜕皮周期中是如何维持和更新的。在幼虫生长过程中，每个表皮细胞的大小会增加许多倍，但既不分裂也不死亡。我们跟踪个体从一次蜕皮到下一次蜕皮，追踪标记细胞，发现随着细胞重新定位并改变其相邻细胞，它们的身份会发生变化以进行补偿，并且模式得以保留。采用新命运的单个细胞甚至可能获得新的极性：在第一幼虫阶段形成向前指向体节的一个已识别细胞，在第二和第三幼虫阶段可能会形成向后指向的体节。DOI: http://dx.doi.org/10.7554/eLife.01569.001 。
