Grubbs Nathaniel, Haas Sue, Beeman Richard W, Lorenzen Marcé D
Department of Entomology, North Carolina State University, Raleigh, North Carolina 27695.
U.S. Department of Agriculture-Agricultural Research Service-Center for Grain and Animal Health Research, Manhattan, Kansas 66502.
Genetics. 2015 Mar;199(3):749-59. doi: 10.1534/genetics.114.173971. Epub 2015 Jan 2.
In Drosophila melanogaster, each of the three paralogous ABC transporters, White, Scarlet and Brown, is required for normal pigmentation of the compound eye. We have cloned the three orthologous genes from the beetle Tribolium castaneum. Conceptual translations of Tribolium white (Tcw), scarlet (Tcst), and brown (Tcbw) are 51, 48, and 32% identical to their respective Drosophila counterparts. We have identified loss-of-eye-pigment strains that bear mutations in Tcw and Tcst: the Tcw gene in the ivory (i) strain carries a single-base transversion, which leads to an E → D amino-acid substitution in the highly conserved Walker B motif, while the Tcst gene in the pearl (p) strain has a deletion resulting in incorporation of a premature stop codon. In light of these findings, the mutant strains i and p are herein renamed white(ivory) (w(i)) and scarlet(pearl) (st(p)), respectively. In addition, RNA inhibition of Tcw and Tcst recapitulates the mutant phenotypes, confirming the roles of these genes in normal eye pigmentation, while RNA interference of Tcbw provides further evidence that it has no role in eye pigmentation in Tribolium. We also consider the evolutionary implications of our findings.
在黑腹果蝇中,三种同源ABC转运蛋白White、Scarlet和Brown中的每一种都是复眼正常色素沉着所必需的。我们已经从赤拟谷盗中克隆了这三个同源基因。赤拟谷盗的white(Tcw)、scarlet(Tcst)和brown(Tcbw)的概念性翻译与它们各自的果蝇对应物分别有51%、48%和32%的同一性。我们已经鉴定出在Tcw和Tcst中携带突变的眼色素缺失菌株:象牙色(i)菌株中的Tcw基因发生了单碱基颠换,导致在高度保守的沃克B基序中发生E→D氨基酸替换,而珍珠色(p)菌株中的Tcst基因有一个缺失,导致掺入了一个提前的终止密码子。鉴于这些发现,突变菌株i和p在此分别重新命名为white(ivory)(w(i))和scarlet(pearl)(st(p))。此外,Tcw和Tcst的RNA抑制重现了突变表型,证实了这些基因在正常眼色素沉着中的作用,而Tcbw的RNA干扰提供了进一步的证据,表明它在赤拟谷盗的眼色素沉着中没有作用。我们还考虑了我们研究结果的进化意义。