Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, MA, USA.
Bioessays. 2014 Feb;36(2):151-6. doi: 10.1002/bies.201300136. Epub 2013 Dec 9.
Scaling of pattern with size has been described and studied for over a century, yet its molecular basis is understood in only a few cases. In a recent, elegant study, Inomata and colleagues proposed a new model explaining how bone morphogenic protein (BMP) activity gradient scales with embryo size in the early Xenopus laevis embryo. We discuss their results in conjunction with an alternative model we proposed previously. The expansion-repression mechanism (ExR) provides a conceptual framework unifying both mechanisms. Results of Inomata and colleagues implicate the chordin-stabilizing protein sizzled as the expander molecule enabling scaling, while we attributed this role to the BMP ligand Admp. The two expanders may work in concert, as suggested by the mathematical model of Inomata et al. We discuss approaches for differentiating the contribution of sizzled and Admp to pattern scaling.
形态大小的缩放已经被描述和研究了一个多世纪，但在少数情况下才了解其分子基础。在最近一项优雅的研究中，稻村及其同事提出了一个新模型，解释了骨形态发生蛋白（BMP）活性梯度如何在早期非洲爪蟾胚胎中随胚胎大小缩放。我们结合之前提出的另一种模型讨论了他们的结果。扩展-抑制机制（ExR）提供了一个统一两种机制的概念框架。稻村等人的研究结果表明，Chordin 稳定蛋白 Sizzled 是实现缩放的扩展分子，而我们则将这一角色归因于 BMP 配体 Admp。正如稻村等人的数学模型所表明的那样，这两种扩展因子可能协同工作。我们讨论了区分 sizzled 和 Admp 对模式缩放的贡献的方法。
