Wee Jocelyn Liang Qi, Das Banerjee Tirtha, Prakash Anupama, Seah Kwi Shan, Monteiro Antonia
Department of Biological Sciences, National University of Singapore, 16 Science Drive 4, Block S2 01-03, Singapore, 117558, Singapore.
Yale-NUS College, College Ave West, Singapore, 138527, Singapore.
Evodevo. 2022 Jun 3;13(1):12. doi: 10.1186/s13227-022-00197-2.
Two genes, Distal-less (Dll) and spalt (sal), are known to be involved in establishing nymphalid butterfly wing patterns. They function in several ways: in the differentiation of the eyespot's central signalling cells, or foci; in the differentiation of the surrounding black disc; in overall scale melanisation (Dll); and in elaborating marginal patterns, such as parafocal elements. However, little is known about the functions of these genes in the development of wing patterns in other butterfly families. Here, we study the expression and function of Dll and sal in the development of spots and other melanic wing patterns of the Indian cabbage white, Pieris canidia, a pierid butterfly. In P. canidia, both Dll and Sal proteins are expressed in the scale-building cells at the wing tips, in chevron patterns along the pupal wing margins, and in areas of future scale melanisation. Additionally, Sal alone is expressed in the future black spots. CRISPR knockouts of Dll and sal showed that each gene is required for the development of melanic wing pattern elements, and repressing pteridine granule formation, in the areas where they are expressed. We conclude that both genes likely play ancestral roles in organising distal butterfly wing patterns, across pierid and nymphalid butterflies, but are unlikely to be differentiating signalling centres in pierids black spots. The genetic and developmental mechanisms that set up the location of spots and eyespots are likely distinct in each lineage.
已知两个基因，无翅（Distal-less，Dll）和spalt（sal），参与蛱蝶科蝴蝶翅膀图案的形成。它们以多种方式发挥作用：在眼斑的中央信号细胞或焦点的分化中；在周围黑色圆盘的分化中；在整体鳞片黑化过程中（Dll）；以及在细化边缘图案，如副焦点元素中。然而，对于这些基因在其他蝴蝶科翅膀图案发育中的功能知之甚少。在这里，我们研究了Dll和sal在粉蝶科蝴蝶印度菜粉蝶（Pieris canidia）斑点和其他黑色翅膀图案发育中的表达和功能。在印度菜粉蝶中，Dll和Sal蛋白均在翅尖的鳞片构建细胞中、沿蛹翅边缘的人字形图案中以及未来鳞片黑化的区域中表达。此外，只有Sal在未来的黑色斑点中表达。Dll和sal的CRISPR基因敲除表明，每个基因在其表达区域对于黑色翅膀图案元素的发育以及抑制蝶啶颗粒形成都是必需的。我们得出结论，这两个基因可能在组织粉蝶科和蛱蝶科蝴蝶的远端翅膀图案中发挥着祖先的作用，但不太可能是粉蝶科蝴蝶黑色斑点中的分化信号中心。在每个谱系中，确定斑点和眼斑位置的遗传和发育机制可能是不同的。
