Isolation of plasma membranes, Golgi bodies and mitochondria of Xenopus laevis morulae. Identification of plasma membrane proteins.
Homogenates of Xenopus morulae at the 16-32 cell stage were centrifuged on discontinuous sucrose gradients. Isolated fractions were identified by electron microscopy (EM) as mitochondria, a fraction enriched in Golgi vesicles, and plasma membranes. A special effort was made to prepare plasma membranes free of cytoplasmic contaminants. The resulting purified plasma membranes appeared morphologically identical to plasma membranes in situ. The external surface is covered with a fibrillar coat while vesicles are seen attached to their inner surface. O'Farell's method (1975) was used to obtain protein patterns of the various fractions on 2-dimensional gel electrophoresis. Each fraction displayed a specific pattern. By comparing the different patterns, it was possible to identify a group of proteins as belonging to the plasma membrane fractions. Labelling of cell surface with sulfo-N-hydroxysuccinimido-biotin together with differential extraction of proteins has allowed us to tentatively allocate these proteins in different structures of the plasma membrane fractions. The data presented in this paper corroborate and extend our ultrastructural studies on neogenesis of interblastomeric plasma membranes (Bieliavsky and Geuskens, 1990).
Bieliavsky
N
N
Département de Biologie Moléculaire, Université Libre de Bruxelles, Rhode-St-Genèse, Belgium.
Geuskens
M
M
Goldfinger
M
M
Tencer
R
R
D000818:Animals; D001710:Biotin; D002458:Cell Fractionation; D002462:Cell Membrane / Q000737:chemistry / Q000648:ultrastructure; D015180:Electrophoresis, Gel, Two-Dimensional; D006056:Golgi Apparatus / Q000737:chemistry; D008565:Membrane Proteins / Q000032:analysis*; D008928:Mitochondria / Q000737:chemistry; D009028:Morula / Q000737:chemistry*; D014909:Wheat Germ Agglutinins; D014981:Xenopus
D008565:Membrane Proteins; D014909:Wheat Germ Agglutinins; D001710:Biotin