Endocrine Regulation of the Ecdysteroid Cascade During Insect Metamorphosis

雷迪福德变形记涉及到一种壮观的形式变化，例如将一只毛毛虫变成一只可爱的蝴蝶。里迪福德博士试图了解荷尔蒙调节的细胞和分子基础，这是在正确的时间以协调的方式发生这种转变所必需的一系列复杂事件。在昆虫中，幼虫的生长需要其角质层外骨骼的周期性蜕皮，这些蜕皮是由作用于表皮的类固醇激素蜕皮激素启动和协调的，这使得培养物在第二种激素保幼激素的存在下。当蜕皮激素在没有保幼激素的情况下活动时，就会发生变态，导致表皮发生变化，导致一种新型的角质层，并使成体(成体)盘和处理器细胞分化，形成新的成体结构。Riddiford博士将利用蜕皮激素受体及其伴侣超阿司匹林和早期蜕皮激素诱导的转录因子的亚型的抗体，并在必要时进行RNA的原位杂交分析，以研究在烟草角虫幼虫蜕皮期间存在保幼激素的情况下和在没有保幼激素的情况下，烟草天牛变态期间表皮细胞对循环蜕皮类固醇的反应的差异。这些反应将与主要在幼虫生命周期中增殖的想象细胞中的反应进行比较，然后在最后的幼虫阶段早期进行变态，以阐明这两种不同类型的细胞对相同的激素环境做出反应的机制。里迪福德博士还将开发一种方法，当蜕皮激素在体外和动物体内产生反应时，选择性地删除表皮中的一种蜕皮激素受体或诱导的转录因子，以分析这些不同因素在导致蜕皮过程中新的角质层形成和变态所需的细胞开关方面的功能作用。这些研究将提供更深入的了解两种主要的蜕皮激素-蜕皮激素和20-羟基蜕皮激素如何在蜕皮和表皮细胞命运转换期间启动和协调细胞反应，这是变态的标志，以及保幼激素如何指导蜕皮类固醇作用以防止变态。所获得的基本知识也可能导致新的选择性昆虫控制方法。

9817339RiddifordMetamorphosis involves a spectacular change of form such as the transformation of a caterpillar into a lovely butterfly. Dr. Riddiford seeks to understand the cellular and molecular basis of the hormonal regulation of the complex series of events necessary for this transformation to occur in a coordinated manner at the right time. In insects the growth of the larva requires periodic molts of its cuticular exoskeleton which are initiated and coordinated by the steroid hormone ecdysone acting on the epidermis which makes the culticle in the presence of a second hormone juvenile hormone. Metamorphosis occurs when ecdysone acts in the absence of juvenile hormone, causing changes in the epidermis that lead to a new type of cuticle and the differentiation of imaginal (adult) discs and processor cells to form new adult structures. Dr. Riddiford will utilize antibodies to the isoforms of the ecdysone receptor and its partner ultraspiracle and of the early ecdysteroid-induced transcription factors and when necessary, in situ hybridization analysis of the RNAs, to study differences in epidermal cell response to the circulating ecdysteroids in the presence of juvenile hormone during a larval molt and in its absence during metamorphosis of the tobacco hornworm, Manduca sexta. These responses will be compared to those in the imaginal cells which mainly proliferate during larval life, then become committed for metamorphosis early in the final larval stage to elucidate the mechanism whereby these two different types of cells respond to the same hormonal milieu. Dr. Riddiford will also develop a method of selectively deleting one of the ecdysone receptors or the induced transcription factors in the epidermis when it is responding to ecdysteroid in vitro and then in the animal so as to assay the functional roles of these various factors in causing both new cuticle formation during the molts and the cellular switches necessary for metamorphosis. These studies will provide deeper insight into how the two major ecdysteroids, ecdysone and 20-hydroxyecdysone, initiate and coordinate the cellular responses during a molt and during the switching of the epidermal cell fate that is the hallmark of metamorphosis and how juvenile hormone directs ecdysteroid action to prevent metamorphosis. The basic knowledge gained also may lead to new selective approaches to insect control.