MEDIATION OF DROSOPHILA HEAD DEVELOPMENT BY GAP-LIKE SEGMENTATION GENES
MEDIATION OF DROSOPHILA HEAD DEVELOPMENT BY GAP-LIKE SEGMENTATION GENES
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DOI：
10.1038/346482a0
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发表时间：
1990-08-02
期刊：
影响因子：
64.8
通讯作者：
JURGENS, G
中科院分区：
文献类型：
--
作者：
COHEN, SM;JURGENS, G
果蝇胚胎发育的第一阶段包括对母体编码的信息的加工和解释，这些信息规定了胚胎中的空间模式。母体类基因（bcd）的产物被认为组织了胚胎的前部模式。尽管bed转录本位于卵子的前极3，4，但bed蛋白在胚胎的前三分之二形成稳定的浓度梯度5。bed蛋白的分级分布通过次级靶点如差距基因hunchback（hb）7-11的空间限制性激活，确定了沿着胚胎前后轴的位置6 - 8。体外对bcd蛋白特异性结合位点的操作表明，bed蛋白的梯度原则上可以在胚胎头部定义一个以上的空间限制性基因激活的离散域，这取决于bcd蛋白可用结合位点的亲和力8.12。遗传分析表明，需要至少一个额外的合子分割基因来介导位于hb结构域之前的头部部分的bcd功能2，12-14。缺失的基因活性预期在比hb激活所需的更高水平的bed蛋白质的反应中被激活12。我们在这里报告了三个先前鉴定的合子基因buttonhead（btd），empty spiracles（ems）和orthodenticle（otd）l5- 17可能表现为gap基因，在胚胎头部介导床功能。
THE first phase of embryonic development inDrosophilaconsists of the elaboration and interpretation of maternally encoded information that specifies spatial pattern in the embryo1. The product of the maternal genebicoid(bcd) is thought to organize the anterior pattern of the embryo2. Although the bed transcript is localized at the anterior pole of the egg3,4the bed protein forms a stable concentration gradient through the anterior two thirds of the embryo5. The graded distribution of bed protein defines position along the anterior-posterior axis of the embryo6–8through the spatially restricted activation of subordinate targets such as the gap genehunchback(hb)7–11. In vitro manipulation of specificbcdprotein binding sites has shown that the gradient of bed protein can in principle define more than one discrete domain of spatially restricted gene activation in the head of the embryo, depending on the affinity of the available binding sites for thebcdprotein8.12. Genetic analysis has indicated the need for at least one additional zygotic segmentation gene to mediatebcdfunction in portions of the head that lie anterior to thehbdomain2,12–14. The missing gene activity is expected to be activated in response to higher levels of bed protein than are required forhbactivation12. We report here that three previously identified zygotic genesbuttonhead(btd),empty spiracles(ems) andorthodenticle(otd)l5–17may behave like gap genes that mediate bed function in the embryonic head.