Struhl G
Howard Hughes Medical Institute, Columbia University College of Physicians and Surgeons, New York, New York 10032.
Nature. 1989 Apr 27;338(6218):741-4. doi: 10.1038/338741a0.
Opposing anterior and posterior morphogen systems specify the segmented body pattern of Drosophila. The anterior morphogen, bicoid, exerts a direct, instructive influence on head and thoracic pattern by triggering different outcomes according to changes in its concentration along the body. In contrast, the posterior morphogen, nanos, simply defines where abdominal patterning can occur by eliminating an otherwise ubiquitous repressor, hunchback protein, from the posterior half of the embryo. Within this hunchback-free domain the pattern of abdominal segments must be specified by other morphogens, possibly by shorter range gradients of the products of zygotic gap genes Kruppel, knirps and tailless.
前后形态发生素系统相互拮抗，决定了果蝇的分节身体模式。前部形态发生素双胸蛋白通过根据其沿身体浓度的变化触发不同结果，对头部和胸部模式产生直接的指导作用。相比之下，后部形态发生素纳米蛋白只是通过从胚胎后半部分消除一种原本普遍存在的阻遏物驼背蛋白，来定义腹部模式可能出现的位置。在这个没有驼背蛋白的区域内，腹部节段的模式必须由其他形态发生素指定，可能是由合子间隙基因克虏伯、无尾和无尾产物的较短范围梯度指定。
