Ingham P W, Baker N E, Martinez-Arias A
Imperial Cancer Research Fund, Department of Zoology, Oxford, UK.
Nature. 1988 Jan 7;331(6151):73-5. doi: 10.1038/331073a0.
During the late cellular blastoderm stage of Drosophila embryo-genesis the segmentation genes engrailed, en, and wingless, wg, become expressed in two series of 14 stripes which will subsequently coincide with the anterior and posterior limits of each parasegment. Previous studies have shown that the establishment of the pattern of en stripes depends upon the activity of the homoeobox-containing pair-rule genes fushi tarazu, ftz and even skipped, eve. Here we show that these two genes also control the spatial expression of wg. Whereas ftz and eve behave as activators of en we find that both genes are required to repress wg expression, so that wg becomes expressed only in the narrow stripes of cells which come to separate the ftz and eve bands at the end of the blastoderm stage. In contrast, we propose that the precise positioning of the en stripes depends upon signals generated in a combinatorial manner by the overlaps between the ftz or eve domains and those of other pair rule genes, specifically odd paired, opa and paired, prd.
在果蝇胚胎发育的晚期细胞胚盘阶段，分节基因engrailed（en）和无翅基因（wingless，wg）在14条带纹的两个系列中表达，这些带纹随后将与每个副节的前后边界重合。先前的研究表明，en带纹模式的建立依赖于含同源异型框的成对规则基因条纹不足（fushi tarazu，ftz）和偶数缺失（even skipped，eve）的活性。在此我们表明，这两个基因也控制wg的空间表达。虽然ftz和eve作为en的激活因子起作用，但我们发现这两个基因都需要抑制wg的表达，从而使得wg仅在胚盘阶段末期分隔ftz和eve带的狭窄细胞带中表达。相反，我们提出，en带纹的精确定位依赖于由ftz或eve结构域与其他成对规则基因（特别是奇数配对基因opa和配对基因prd）之间的重叠以组合方式产生的信号。
