THE SURFACE FEATURES OF DROSOPHILA EMBRYONIC CELL LINES

qchneider’s cell lines 1, 2 and 3 derived from embryonic stages of Drosophila rnelanogaster were examined by scanning electron microscopy, histochemical staining procedures, and SDS polyacrylamide disc gel electrophoresis. Although the three lines showed some similarities when compared by each of these methods, differences between the lines were observed as well. The surface features of the cells in each line showed morphologic as well as age dependent distinctions when examined in the scanning electron microscope. The intracellular distribution and amount of periodic acid-Schiff positive (PAS+), a-amylase sensitive material was also distinct for each of the lines. Approximately one-third of line 1 cells contained PAS+ hyaluronidase-sensitive material localized within a cytoplasmic vesicle whereas less than 1% of the cells of lines 2 and 3 contained such material. SDS polyacrylamide disc gel electrophoresis revealed PAS+ material in a soluble fraction of line 2 cells and in the 100,000 X g pellet of line 3 cells, but no PAS+ bands in similar fractions of line 1 cells were detected. Methods for establishing stable cell lines .of Drosophila melanogaster have been developed within the past several years (10, 24), and it is anticipated that this material will prove particularly useful for studying the biology of cells in vitro as well as analyzing various developmental features in this species which is so widely used for genetic experimentation. Schneider’s cell lines 1, 2 and 3 (24) have already been exploited to examine a number of problems in cell biology. Of particular interest are the nuclear transplantation studies of ILLMENSEE (14) using these in vitro cells. To test the ability of nuclei from these cultured cells to promote differentiation of Drosophila tissues, ILLMENSEE (14) injected the nuclei into cleavage embryos thus allowing the implanted nuclei the opportunity to become integrated into cells during cellular blastoderm formation. By the use of genetically marked eggs, the fate of the descendants of the implanted nuclei could be recognized as mosaic patches of cells among the cells of the host embryos. These implantation studies demonstrated that the potential for differentiation of the three cell lines differed. Nuclei of line 1 participated in the development of both larval‘and adult tissues, line 2 nuclei were restricted to larval tissues, and nuclei of line 3 cells had lost these embryonic potentialities. The specific tissue from which Schneider’s lines originated is not known because the lines were derived from trypsinized fragments of late embryos. Since embryonic cells from the primary cultures underwent metamorphosis to form adult structures when tested in host larvae, SCHNEIDER (24) suggested that the cell lines are derivatives of imaginal discs. She reported differences in the growth characteristics of the three lines, and more recently quantitative differences in the agglutination responses to wheat germ agglutinin and concanavalin A were found among the cell lines (3). The present study was undertaken to further characterize these three cell lines. Since heterogeneity of response to lectin-induced agglutination may be due in part to differences in carbohydrate-containing surface structures, the surface topography of