Department of Biological Sciences, National University of Singapore, Singapore 117558.
Mechanobiology Institute, National University of Singapore, Singapore 117411.
Development. 2019 May 9;146(9):dev169367. doi: 10.1242/dev.169367.
Eyespots on the wings of nymphalid butterflies represent colorful examples of pattern formation, yet the developmental origins and mechanisms underlying eyespot center differentiation are still poorly understood. Using CRISPR-Cas9 we re-examine the function of Distal-less (Dll) as an activator or repressor of eyespots, a topic that remains controversial. We show that the phenotypic outcome of CRISPR mutations depends upon which specific exon is targeted. In , exon 2 mutations are associated with both missing and ectopic eyespots, and also exon skipping. Exon 3 mutations, which do not lead to exon skipping, produce only null phenotypes, including missing eyespots, lighter wing coloration and loss of scales. Reaction-diffusion modeling of Dll function, using Wnt and Dpp as candidate morphogens, accurately replicates these complex crispant phenotypes. These results provide new insight into the function of Dll as a potential activator of eyespot development, scale growth and melanization, and suggest that the tuning of Dll expression levels can generate a diversity of eyespot phenotypes, including their appearance on the wing.This article has an associated 'The people behind the papers' interview.
眼斑是蛱蝶翅膀上具有代表性的色彩图案，但眼斑中心分化的发育起源和机制仍知之甚少。我们使用 CRISPR-Cas9 重新研究了 Distal-less (Dll) 作为眼斑激活或抑制因子的功能，这一问题仍然存在争议。我们表明，CRISPR 突变的表型结果取决于靶向的特定外显子。在 中，外显子 2 突变与缺失和异位眼斑以及外显子跳跃有关。不会导致外显子跳跃的外显子 3 突变只会产生纯合表型，包括缺失眼斑、翅膀颜色变浅和鳞片缺失。使用 Wnt 和 Dpp 作为候选形态发生素的 Dll 功能反应扩散模型，准确复制了这些复杂的crispr 表型。这些结果为 Dll 作为眼斑发育、鳞片生长和黑化的潜在激活因子的功能提供了新的见解，并表明 Dll 表达水平的调整可以产生多种眼斑表型，包括它们在翅膀上的出现。本文有一个相关的“论文背后的人物”采访。
