Melanin-synthesis enzymes coregulate stage-specific larval cuticular markings in the swallowtail butterfly, Papilio xuthus
Melanin-synthesis enzymes coregulate stage-specific larval cuticular markings in the swallowtail butterfly, Papilio xuthus
复制标题
DOI：
10.1007/s00427-005-0014-y
复制
发表时间：
2005-10-01
影响因子：
2.4
通讯作者：
Fujiwara, H
中科院分区：
文献类型：
--
作者：
Futahashi, R;Fujiwara, H
与成虫翅膀一样，蝴蝶幼虫的颜色也很独特。然而，昆虫幼虫颜色图案形成的分子机制在很大程度上尚不清楚。燕尾蝶 Papilio xuthus 的幼虫在第四次蜕皮期间显着改变其颜色图案。我们研究了它的角质层颜色模式，它被认为是由黑色素和酪氨酸衍生的相关色素组成。我们克隆了 P. xuthus 中参与黑色素合成途径的三种酶：酪氨酸羟化酶 (TH)、多巴脱羧酶 (DDC) 和乌木。整体原位杂交显示TH和DDC的表达与黑色标记密切相关。乌木色仅在红棕色区域表现强烈。每种酶的表达模式与后续龄期的角质层颜色模式一致。我们还研究了培养的珠被对黑色素前体的吸收。抑制 TH 或 DDC 活性可完全防止体外色素沉着。在 TH 抑制剂存在的情况下向珠被添加多巴胺会导致整体变暗，而没有特定的标记。从这些结果来看，特定的幼虫角质层颜色模式是通过表皮细胞中酶的阶段特异性共定位来调节的，而不是通过个体表皮细胞对黑色素前体的差异摄取来调节的。表达 TH 和 DDC（但不表达乌木色）的表皮细胞产生黑色角质层，表达 TH、DDC 和乌木色的表皮细胞产生红棕色角质层。
Like the adult wing, butterfly larvae are unique in their coloring. However, the molecular mechanisms underlying the formation of insect larval color patterns are largely unknown. The larva of the swallowtail butterfly Papilio xuthus changes its color pattern markedly during the 4th ecdysis. We investigated its cuticular color pattern, which is thought to be composed of melanin and related pigments derived from tyrosine. We cloned three enzymes involved in the melanin-synthesis pathway in P. xuthus: tyrosine hydroxylase (TH), dopa decarboxylase (DDC), and ebony. Whole-mount in situ hybridization showed that the expression of both TH and DDC is strongly correlated with the black markings. ebony is strongly expressed only in the reddish-brown area. The expression pattern of each enzyme coincides with the cuticular color pattern of the subsequent instar. We also investigated the uptake of melanin precursors into cultured integument. Inhibition of either TH or DDC activity prevents in vitro pigmentation completely. Addition of dopamine to integuments in the presence of TH inhibitor causes overall darkening without specific markings. From these results, specific larval cuticular color patterns are regulated by stage-specific colocalization of enzymes in epidermal cells rather than by the differential uptake of melanin precursors into individual epidermal cells. Epidermal cells expressing TH and DDC, but not ebony, produce the black cuticle, and epidermal cells expressing TH, DDC, and ebony produce the reddish-brown cuticle.