EYESPOT DEVELOPMENT ON BUTTERFLY WINGS - THE FOCAL SIGNAL
EYESPOT DEVELOPMENT ON BUTTERFLY WINGS - THE FOCAL SIGNAL
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DOI：
10.1006/dbio.1995.1065
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发表时间：
1995-03-01
影响因子：
2.7
通讯作者：
BRAKEFIELD, PM
中科院分区：
文献类型：
--
作者：
FRENCH, V;BRAKEFIELD, PM
蝴蝶翅膀上的眼斑颜色图案是由早期蛹表皮上的一个中心“焦点”发出的信号决定的。“在双环蝇中，我们发现一个小正方形的局灶表皮，嫁接到远端翅膀的一些部位，在周围的宿主组织中诱导形成眼斑。信号仅局限于焦点，甚至相邻的（副焦点）移植物也不能维持其正常的命运（形成眼点），也不会影响其周围环境。沿着翅膀，表皮发生突变，因为移植物到近端没有引起宿主反应。几个移植实验的结果表明，它们的不同响应特性是自主的远端和近端表皮的小区域，而无响应的近端组织仍然可以传递病灶信号。双车虫的背翅有一个小的前眼点和一个大的后眼点，我们发现这主要是由于局灶信号的差异，而不是表皮反应的差异。移植后焦引起大的眼斑，而前焦引起小的眼斑。此外，前后眼点的比例不同，这种差异也取决于焦点的身份，而不是响应表皮。眼点是由一种机制指定的，这种机制可以由一个远程信号组成，如形态发生梯度或由焦点引发的一系列短程相互作用。焦点控制的大小和比例的差异之间的前和后眼点是更容易兼容的梯度机制。然而，这两种模型都不能很好地解释为什么嫁接焦点诱导的图案更小，但其周围的金环比相应的对照眼点更宽。此外，在蝴蝶翅膀或任何其他昆虫的上皮中，也没有直接的证据表明存在远距离梯度。(C) 1995学术出版社，Inc。
The eyespot colour pattern on butterfly wings is specified in the early pupal epidermis by signals from a central ''focus.'' In Bicyclus anynana we show that a small square of focal epidermis, grafted to a range of distal wing sites, induces eyespot formation in surrounding host tissue. Signaling is limited to the focus, and even an adjacent (parafocal) graft does not maintain its normal fate (of contributing to the eyespot) and does not influence its surroundings. Along the wing, there is an abrupt change in the epidermis, as a focus grafted to a proximal site provokes no host response. The results of several grafting experiments demonstrate that their different response properties are autonomous to small areas of the distal and proximal epidermis and that the nonresponding proximal tissue can nonetheless transmit the focal signal. The Bicyclus dorsal forewing has a small anterior and a large posterior eyespot, and we show that this results mainly from a difference in focal signals, not in the epidermal response. A grafted posterior focus induces a large eyespot, whereas an anterior focus induces a small eyespot. Furthermore, the anterior and posterior eyespots differ in proportions, and this difference also depends on the identity of the focus, not on the responding epidermis. Eyespots are specified over many cell diameters from the focus by a mechanism which could consist of one long-range signal, such as a morphogen gradient or of a cascade of short-range interactions initiated by the focus. Focal control of the difference in size and proportion between the anterior and posterior eyespot is more readily compatible with a gradient mechanism. Neither model, however, readily explains why the pattern induced by a grafted focus is smaller, but its peripheral gold annulus is broader than in the corresponding control eyespot. Also, there is no direct evidence for long-range gradients, in the butterfly wing or any other insect epithelium. (C) 1995 Academic Press,Inc.