Mlodzik M, Gehring W J
Cell. 1987 Feb 13;48(3):465-78. doi: 10.1016/0092-8674(87)90197-8.
The caudal (cad) gene of Drosophila encodes a maternal and a zygotic transcript which have different promoters. Both mRNAs contain the same open reading frame, including a homeo box. In situ hybridization and antibody staining show that the maternal RNA and protein are localized in an anteroposterior gradient during the syncytial blastoderm stage. The protein is found mainly in the nuclei and is also present in the pole cells. Zygotic RNA and protein are localized in the primordia of the terminal abdominal segment, the hindgut, and in the posterior midgut rudiment. In third instar larvae, cad is expressed in the gut, the gonads, and parts of the genital discs. It is the first homeo box-containing gene expressed in the germ line of Drosophila.
果蝇的尾（cad）基因编码一种母体转录本和一种合子转录本，它们具有不同的启动子。两种mRNA都包含相同的开放阅读框，包括一个同源异型框。原位杂交和抗体染色表明，母体RNA和蛋白质在合胞体胚盘阶段以前后梯度定位。该蛋白质主要存在于细胞核中，也存在于极细胞中。合子RNA和蛋白质定位在腹部末端节段的原基、后肠以及中肠后部原基中。在三龄幼虫中，cad在肠道、性腺和部分生殖盘表达。它是果蝇生殖系中表达的第一个含同源异型框的基因。
