Woods Daniel F, Rickoll Wayne L, Birr Cynthia, Poodry Clifton A, Fristrom James W
Department of Biology, University of California, 95064, Santa Cruz, California.
Department of Genetics, University of California, 94720, Berkeley, California, USA.
Rouxs Arch Dev Biol. 1987 Sep;196(6):339-346. doi: 10.1007/BF00375770.
Unevaginated and evaginated Drosophila imaginal discs were surface-labeled with I. Relative labeling was greater in eleven peptides and lower in three peptides of evaginated discs compared to unevaginated discs. These results are compared to the effects of 20-hydroxyecdysone (20-HOE) on metabolic labeling of membrane proteins fractionated from imaginal discs, and on cell surface labeling of a hormone-responsive Drosophila tissue culture line. A group of S-methionine labeled membrane fraction peptides whose metabolic labeling is 20-HOE dependent have isoelectric points and apparent molecular weights very similar to those of a group of proteins only labeled in iodinated evaginated discs, supporting the conclusion that these are hormone-dependent, cell surface proteins (Rickoll and Fristrom 1983). Based upon two-dimensional gel electrophoretic and immunological criteria three of the proteins showing increased labeling in evaginated discs are related to three proteins induced by 20-HOE in tissue culture cells. Two different subsets of radiolabeled peptides were observed in the imaginal discs based upon detergent solubility. Some of the proteins which are soluble in NP-40 plus urea but insoluble in NP-40 alone may be localized in the basal lamina of the imaginal discs, a structure which labels heavily with I and is lacking in tissue culture cells. In discs, the majority of hormone-dependent changes in radiolabeled peptides were seen in the fraction solubilized by NP-40 and urea with a sulfhydryl reducing agent, while in tissue culture cells, the majority of differences is seen in the fraction solubilized by NP-40 only. We speculate that these proteins may be involved in similar processes, e.g., cell rearrangement, that occur during both disc morphogenesis and 20-HOE induced aggregation in tissue culture cells.
对内翻和外翻的果蝇成虫盘进行表面碘化标记。与内翻的成虫盘相比，外翻成虫盘的11种肽的相对标记率更高，3种肽的相对标记率更低。将这些结果与20-羟基蜕皮激素（20-HOE）对从成虫盘中分离出的膜蛋白代谢标记的影响，以及对激素反应性果蝇组织培养细胞的细胞表面标记的影响进行了比较。一组代谢标记依赖于20-HOE的S-甲硫氨酸标记的膜组分肽，其等电点和表观分子量与仅在碘化外翻成虫盘中标记的一组蛋白质非常相似，这支持了这些是激素依赖性细胞表面蛋白的结论（里科尔和弗里斯特罗姆，1983年）。基于二维凝胶电泳和免疫学标准，在翻盘中标记增加的三种蛋白质与组织培养细胞中由20-HOE诱导的三种蛋白质相关。根据去污剂溶解度，在成虫盘中观察到两个不同的放射性标记肽亚组。一些可溶于NP-40加尿素但不溶于单独NP-40的蛋白质可能定位于成虫盘的基底层，这是一种在碘化时标记强烈且在组织培养细胞中不存在的结构。在成虫盘中，放射性标记肽的大多数激素依赖性变化出现在用NP-40和尿素以及巯基还原剂溶解的组分中，而在组织培养细胞中，大多数差异出现在仅用NP-40溶解的组分中。我们推测这些蛋白质可能参与了在成虫盘形态发生和组织培养细胞中20-HOE诱导的聚集过程中发生的类似过程，例如细胞重排。
