title: Protein storage vacuoles form de novo during pea cotyledon development.
abstract: We have investigated the formation of protein storage vacuoles in peas (Pisum sativum L.) in order to determine whether this organelle arises de novo during cotyledon development. A comparison of different stages in cotyledon development indicates that soluble protease activities decline and the amounts of storage proteins and the integral membrane protein of the protein body, alpha-TIP, increase during seed maturation. On linear sucrose density gradients we have been able to distinguish between two separate vesicle populations: one enriched in alpha-TIP, and one in TIP-Ma 27, a membrane protein characteristic of vegetative vacuoles. Both vesicle populations possess, however, PPase and V-ATPase activities. Conventionally fixed cotyledonary tissue at an intermediate stage in cotyledon development reveals the presence of a complex tubular-cisternal membrane system that seems to surround the pre-existing vacuoles. The latter gradually become compressed as a result of dilation of the former membrane system. This was confirmed immunocytochemically with the TIP-Ma 27 antiserum. Deposits of the storage proteins vicilin and legumin in the lumen, and the presence of alpha-TIP in the membranes of the expanding membrane system provide evidence of its identity as a precursor to the protein storage vacuole.
authors.affiliation: Abteilung Cytologie des Pflanzenphysiologischen Instituts, Universitäts, Göttingen, FRG.
authors.forename: B
authors.initials: B
authors.lastname: Hoh
authors.forename: G
authors.initials: G
authors.lastname: Hinz
authors.forename: B K
authors.initials: BK
authors.lastname: Jeong
authors.forename: D G
authors.initials: DG
authors.lastname: Robinson
mesh_terms: D000251:Adenosine Triphosphatases / Q000032:analysis; D002458:Cell Fractionation; D002462:Cell Membrane / Q000648:ultrastructure; D018548:Cotyledon / Q000648:ultrastructure; D010450:Endopeptidases / Q000032:analysis / Q000378:metabolism; D008565:Membrane Proteins / Q000032:analysis; D008854:Microscopy, Electron; D016253:Microscopy, Immunoelectron; D015388:Organelles / Q000502:physiology / Q000648:ultrastructure*; D018532:Pisum sativum / Q000254:growth & development / Q000648:ultrastructure*; D010940:Plant Proteins / Q000032:analysis* / Q000096:biosynthesis; D011755:Pyrophosphatases / Q000032:analysis; D014617:Vacuoles / Q000648:ultrastructure*
chemical_list: D008565:Membrane Proteins; D010940:Plant Proteins; C078044:alpha-TIP protein, Phaseolus vulgaris; D010450:Endopeptidases; D000251:Adenosine Triphosphatases; D011755:Pyrophosphatases