title: Alterations in the cell surface proteins of Drosophila during morphogenesis.
abstract: Unevaginated and evaginated Drosophila imaginal discs were surface-labeled with125I. 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 of35S-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 with125I 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.
authors.affiliation: Department of Biology, University of California, 95064, Santa Cruz, California.
authors.forename: Daniel F
authors.initials: DF
authors.lastname: Woods
authors.affiliation: Department of Genetics, University of California, 94720, Berkeley, California, USA.
authors.forename: Wayne L
authors.initials: WL
authors.lastname: Rickoll
authors.affiliation: Department of Genetics, University of California, 94720, Berkeley, California, USA.
authors.forename: Cynthia
authors.initials: C
authors.lastname: Birr
authors.affiliation: Department of Biology, University of California, 95064, Santa Cruz, California.
authors.forename: Clifton A
authors.initials: CA
authors.lastname: Poodry
authors.affiliation: Department of Genetics, University of California, 94720, Berkeley, California, USA.
authors.forename: James W
authors.initials: JW
authors.lastname: Fristrom
keywords: Drosophila; Evagination; Hormone depending; Imaginal disc; Radiolabeling; Surface peptides