Drosophila wing melanin patterns form by vein-dependent elaboration of enzymatic prepatterns
Drosophila wing melanin patterns form by vein-dependent elaboration of enzymatic prepatterns
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DOI：
10.1016/s0960-9822(00)80083-4
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发表时间：
1999-12-02
期刊：
影响因子：
9.2
通讯作者：
Carroll, SB
中科院分区：
文献类型：
--
作者：
True, JR;Edwards, KA;Carroll, SB
背景：动物的黑色素模式涉及其生态的不同方面，从体温调节到拟态。许多理论模型已经模拟了色素图案形成，但对颜色图案形成的发展机制知之甚少。在果蝇中，已知有几个基因是皮肤黑化所必需的，但这些基因在黑色素模式进化中的参与尚不清楚。我们采用遗传学的方法来阐明不同果蝇黑色素模式形成的发育机制。结果：我们发现，在黑腹果蝇中，黑色素的合成需要酪氨酸羟基酶(TH)和多巴脱羧酶(DDC)。TH的异位表达，但不是DDC，单独足以引起翅膀中的异位黑色素图案。因此，单个基因表达水平的变化可以导致新的黑化水平。这种异位黑化的个体发育类似于在带有翅膀黑色素图案的果蝇物种和黑腹乌木突变体中发现的个体发育。重要的是，我们发现在黑腹果蝇和其他三种果蝇中，这些翅膀黑色素图案依赖于翼脉中血淋巴的循环模式，并由其形成。结论：复杂的翅膀黑色素图案由两种不同的发育机制决定。酶活性的空间前驱模式是在翅膀发育后期建立的。然后，在新分离的成虫中，黑色素前体逐渐从翅膀静脉扩散出来，并被氧化成深棕色或黑色的黑色素。这个系统的前图案和血淋巴供应的成分在进化过程中都会发生变化，以产生颜色图案多样性。
Background: Animal melanin patterns are involved in diverse aspects of their ecology, from thermoregulation to mimicry. Many theoretical models have simulated pigment patterning, but little is known about the developmental mechanisms of color pattern formation. in Drosophila melanogaster, several genes are known to be necessary for cuticular melanization, but the involvement of these genes in melanin pattern evolution is unknown. We have taken a genetic approach to elucidate the developmental mechanisms underlying melanin pattern formation in various drosophilids.Results:We show that, in D. melanogaster, tyrosine hydroxylase (TH) and dopa decarboxylase (DDC) are required for melanin synthesis. Ectopic expression of TH, but not DDC, alone was sufficient to cause ectopic melanin patterns in the wing. Thus, changes in the level of expression of a single gene can result in a new level;of melanization. The ontogeny of this ectopic melanization resembled that found in Drosophila species bearing wing melanin patterns and in D. melanogaster ebony mutants. Importantly, we discovered that in D. melanogaster and three other Drosophila species these wing melanin patterns are dependent upon and shaped by the circulation patterns of hemolymph in the wing veins.Conclusions: Complex wing melanin patterns are determined by two distinct developmental mechanisms. Spatial prepatterns of enzymatic activity are established late in wing development. Then, in newly eclosed adults, melanin precursors gradually diffuse out from wing veins and are oxidized into dark brown or black melanin. Both the prepatterning and hemolymph-supplied components of this system can change during evolution to produce color pattern diversity.