title: Storage globulins pass through the Golgi apparatus and multivesicular bodies in the absence of dense vesicle formation during early stages of cotyledon development in mung bean.
abstract: During seed development and maturation, large amounts of storage proteins are synthesized and deposited in protein storage vacuoles (PSVs). Multiple mechanisms have been proposed to be responsible for transporting storage proteins to PSVs in developing seeds. In this study, a specific antibody was raised against the mung bean (Vigna radiata) seed storage protein 8S globulin and its deposition was followed via immunogold electron microscopy in developing mung bean cotyledons. It is demonstrated that non-aggregated 8S globulins are present in multivesicular bodies (MVBs) in early stages of cotyledon development where neither dense vesicles (DVs) nor a PSV were recognizable. However, at later stages of cotyledon development, condensed globulins were visible in both DVs and distinct MVBs with a novel form of partitioning, with the internal vesicles being pushed to one sector of this organelle. These distinct MVBs were no longer sensitive to wortmannin. This study thus indicates a possible role for MVBs in transporting storage proteins to PSVs during the early stage of seed development prior to the involvement of DVs. In addition, wortmannin treatment is shown to induce DVs to form aggregates and to fuse with the plasma membrane.
authors.affiliation: School of Life Sciences, Centre for Cell and Developmental Biology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China.
authors.forename: Junqi
authors.initials: J
authors.lastname: Wang
authors.forename: Yu Chung
authors.initials: YC
authors.lastname: Tse
authors.forename: Giselbert
authors.initials: G
authors.lastname: Hinz
authors.forename: David G
authors.initials: DG
authors.lastname: Robinson
authors.forename: Liwen
authors.initials: L
authors.lastname: Jiang
mesh_terms: D018548:Cotyledon / Q000378:metabolism*; D007887:Fabaceae / Q000378:metabolism*; D005916:Globulins / Q000378:metabolism*; D006056:Golgi Apparatus / Q000378:metabolism*; D057146:Multivesicular Bodies / Q000378:metabolism*
chemical_list: D005916:Globulins