Tabata T, Kornberg T B
Department of Biochemistry and Biophysics, University of California, San Francisco 94143.
Cell. 1994 Jan 14;76(1):89-102. doi: 10.1016/0092-8674(94)90175-9.
The segment polarity genes hedgehog and engrailed are expressed in identical posterior-compartment-specific patterns in both Drosophila embryos and imaginal discs. We show here that the hedgehog protein is secreted, and it can cross embryo parasegment borders and the anterior-posterior compartment border of imaginal discs to neighboring cells that express neither engrailed nor hedgehog. In these cells, it is localized in discrete punctate structures that are sequestered within the polarized epithelium. Analysis of animals that have expressed hedgehog ectopically, or of a mutant that expresses hedgehog abnormally in the anterior compartment of the wing disc, indicates that hedgehog is involved in regulating patched. In the embryo, hedgehog regulation of patched apparently facilitates patched and wingless expression. In the discs, hedgehog regulation of patched and other genes in the anterior compartment helps to establish the proximodistal axis. We propose that the cell-cell communication mediated by hedgehog links the special properties of compartment borders with specification of the proximodistal axis in imaginal development.
节段极性基因刺猬基因（hedgehog）和 engrailed 在果蝇胚胎和成虫盘的相同后区特异性模式中表达。我们在此表明，刺猬蛋白是分泌型的，它可以穿过胚胎副节边界以及成虫盘的前后区边界到达既不表达 engrailed 也不表达刺猬基因的相邻细胞。在这些细胞中，它定位于极化上皮内隔离的离散点状结构中。对异位表达刺猬基因的动物或翅盘前区异常表达刺猬基因的突变体的分析表明，刺猬基因参与调节 patched。在胚胎中，刺猬基因对 patched 的调节显然促进了 patched 和无翅基因（wingless）的表达。在成虫盘中，刺猬基因对前区 patched 和其他基因的调节有助于建立近远轴。我们提出，由刺猬基因介导的细胞间通讯将节段边界的特殊性质与成虫发育中近远轴的特化联系起来。
