Cooke Thomas F, Fischer Curt R, Wu Ping, Jiang Ting-Xin, Xie Kathleen T, Kuo James, Doctorov Elizabeth, Zehnder Ashley, Khosla Chaitan, Chuong Cheng-Ming, Bustamante Carlos D
Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305, USA.
ChEM-H, Stanford University, Stanford, CA 94305, USA; Stanford Genome Technology Center, Stanford University, Stanford, CA 94305, USA.
Cell. 2017 Oct 5;171(2):427-439.e21. doi: 10.1016/j.cell.2017.08.016.
Parrot feathers contain red, orange, and yellow polyene pigments called psittacofulvins. Budgerigars are parrots that have been extensively bred for plumage traits during the last century, but the underlying genes are unknown. Here we use genome-wide association mapping and gene-expression analysis to map the Mendelian blue locus, which abolishes yellow pigmentation in the budgerigar. We find that the blue trait maps to a single amino acid substitution (R644W) in an uncharacterized polyketide synthase (MuPKS). When we expressed MuPKS heterologously in yeast, yellow pigments accumulated. Mass spectrometry confirmed that these yellow pigments match those found in feathers. The R644W substitution abolished MuPKS activity. Furthermore, gene-expression data from feathers of different bird species suggest that parrots acquired their colors through regulatory changes that drive high expression of MuPKS in feather epithelia. Our data also help formulate biochemical models that may explain natural color variation in parrots. VIDEO ABSTRACT.
鹦鹉的羽毛含有红色、橙色和黄色的多烯色素，称为鹦鹉黄素。虎皮鹦鹉是在上个世纪因其羽毛特征而被广泛培育的鹦鹉，但相关的潜在基因尚不清楚。在此，我们利用全基因组关联图谱和基因表达分析来定位孟德尔蓝色基因座，该基因座可消除虎皮鹦鹉的黄色色素沉着。我们发现蓝色性状定位于一种未表征的聚酮合酶（MuPKS）中的单个氨基酸替换（R644W）。当我们在酵母中异源表达MuPKS时，黄色色素积累。质谱分析证实这些黄色色素与羽毛中发现的色素相匹配。R644W替换消除了MuPKS的活性。此外，来自不同鸟类羽毛的基因表达数据表明，鹦鹉通过调控变化获得了它们的颜色，这些调控变化促使MuPKS在羽毛上皮细胞中高表达。我们的数据也有助于构建可能解释鹦鹉自然颜色变异的生化模型。视频摘要。
