Red Carotenoid Coloration in the Zebra Finch Is Controlled by a Cytochrome P450 Gene Cluster
Red Carotenoid Coloration in the Zebra Finch Is Controlled by a Cytochrome P450 Gene Cluster
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DOI：
10.1016/j.cub.2016.04.047
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发表时间：
2016-06-06
期刊：
影响因子：
9.2
通讯作者：
Slate, Jon
中科院分区：
文献类型：
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作者：
Mundy, Nicholas I.;Stapley, Jessica;Slate, Jon
在脊椎动物中，红色通常涉及性、社会和种间信号传导[1-8]，并且主要由酮类胡萝卜素色素产生。在陆地鸟类中，酮类类胡萝卜素如虾青素通常通过膳食黄色类胡萝卜素的酮化代谢衍生[9，10]。然而，这种基因-环境机制的分子基础仍然不清楚。在这里，我们使用的黄喙突变斑胸草雀（Taeniopygia guttata）调查红色的遗传基础。野生型酮类胡萝卜素不存在于黄嘴鸟的喙和跗骨。黄嘴突变定位于染色体8，靠近一簇细胞色素P450位点（CYP 2 J2样），是类胡萝卜素酮醇酶的候选者。野生型斑胸草雀的基因组中有三个完整的基因：CYP 2 J19 A、CYP 2 J19 B和CYP 2 J 40。在黄嘴鹬中，有多个突变：一个完整的CYP 2 J19基因的丢失，一个修饰的剩余CYP 2 J19基因（CYP 2 J19 yb），以及CYP 2 J 40中的一个非同义SNP。在野生型鸟类中，CYP 2 J19基因座在含酮类胡萝卜素的组织中表达：CYP 2 J19 A仅在视网膜中表达，CYP 2 J19 B在喙和跗骨中表达，并在视网膜中表达不同程度。相比之下，CYP 2 J19 yb的表达在黄嘴鸟的喙中几乎检测不到。CYP 2 J 40具有广泛的组织表达，在野生型和黄嘴之间没有差异。我们的研究结果表明，CYP 2 J19基因是类胡萝卜素酮醇酶的强有力的候选人，并意味着酮化发生在珠被在斑胸草雀。由于细胞色素P450酶包括关键的解毒酶，我们的研究结果提出了有趣的可能性，即红色可能是解毒能力的诚实信号。
Bright-red colors in vertebrates are commonly involved in sexual, social, and interspecific signaling [1-8] and are largely produced by ketocarotenoid pigments. In land birds, ketocarotenoids such as astaxanthin are usually metabolically derived via ketolation of dietary yellow carotenoids [9, 10]. However, the molecular basis of this gene-environment mechanism has remained obscure. Here we use the yellowbeak mutation in the zebra finch (Taeniopygia guttata) to investigate the genetic basis of red coloration. Wildtype ketocarotenoids were absent in the beak and tarsus of yellowbeak birds. The yellowbeak mutation mapped to chromosome 8, close to a cluster of cytochrome P450 loci (CYP2J2-like) that are candidates for carotenoid ketolases. The wild-type zebra finch genome was found to have three intact genes in this cluster: CYP2J19A, CYP2J19B, and CYP2J40. In yellowbeak, there are multiple mutations: loss of a complete CYP2J19 gene, a modified remaining CYP2J19 gene (CYP2J19 yb), and a non-synonymous SNP in CYP2J40. In wild-type birds, CYP2J19 loci are expressed in ketocarotenoid-containing tissues: CYP2J19A only in the retina and CYP2J19B in the beak and tarsus and to a variable extent in the retina. In contrast, expression of CYP2J19 yb is barely detectable in the beak of yellowbeak birds. CYP2J40 has broad tissue expression and shows no differences between wild-type and yellowbeak. Our results indicate that CYP2J19 genes are strong candidates for the carotenoid ketolase and imply that ketolation occurs in the integument in zebra finches. Since cytochrome P450 enzymes include key detoxification enzymes, our results raise the intriguing possibility that red coloration may be an honest signal of detoxification ability.