title: The Dual Roles of the Golgi Transport 1 (GOT1B): RNA Localization to the Cortical Endoplasmic Reticulum and the Export of Proglutelin and α-Globulin from the Cortical ER to the Golgi.
abstract: The rice glup2 lines are characterized by their abnormally high levels of endosperm 57 kDa proglutelins and of the luminal chaperone binding protein (BiP), features characteristic of a defect within the endoplasmic reticulum (ER). To elucidate the underlying genetic basis, the glup2 locus was identified by map based cloning. DNA sequencing of the genomes of three glup2 alleles and wild type demonstrated that the underlying genetic basis was mutations in the Golgi transport 1 (GOT1B) coding sequence. This conclusion was further validated by restoration of normal proglutelin levels in a glup2 line complemented by a GOT1B gene. Microscopic analyses indicated the presence of proglutelin-α-globulin-containing intracisternal granules surrounded by prolamine inclusions within the ER lumen. As assessed by in situ reverse transcriptase polymerase chain reaction (RT-PCR) analysis of developing endosperm sections, prolamine and α-globulin RNAs were found to be mis-targeted from their usual sites on the protein body ER to the cisternal ER, the normal sites of proglutelin synthesis. Our results indicate that GLUP2/GOT1B has a dual role during rice endosperm development. It is required for localization of prolamine and α-globulin RNAs to the protein body ER and for efficient export of proglutelin and α-globulin proteins from the ER to the Golgi apparatus.
authors: Faculty of Agriculture, Kyushu University, Fukuoka 812-8581, Japan.
authors: Masako
authors: M
authors: Fukuda
authors: National Institute of Agrobiological Sciences, Tsukuba, Ibaraki 305-8602, Japan.|Deceased.
authors: Yasushi
authors: Y
authors: Kawagoe
authors: Faculty of Agriculture, Kyushu University, Fukuoka 812-8581, Japan.
authors: Takahiro
authors: T
authors: Murakami
authors: Institute of Biological Chemistry, Washington State University, Pullman, Washington 99164-6340, USA.|Present address: U-TEC Corporation, 648-1 Matsukasa, Yamatokoriyama, Nara 639-1124, Japan.
authors: Haruhiko
authors: H
authors: Washida
authors: Institute of Biological Chemistry, Washington State University, Pullman, Washington 99164-6340, USA.
authors: Aya
authors: A
authors: Sugino
authors: Institute of Biological Chemistry, Washington State University, Pullman, Washington 99164-6340, USA.
authors: Ai
authors: A
authors: Nagamine
authors: Institute of Biological Chemistry, Washington State University, Pullman, Washington 99164-6340, USA.
authors: Thomas W
authors: TW
authors: Okita
authors: Department of General Education, Yamaguchi Prefectural University, Yamaguchi 753-8502, Japan.
authors: Masahiro
authors: M
authors: Ogawa
authors: Faculty of Agriculture, Kyushu University, Fukuoka 812-8581, Japan kumamaru@agr.kyushu-u.ac.jp.
authors: Toshihiro
authors: T
authors: Kumamaru
mesh_terms: D000483:Alleles; D000510:Alpha-Globulins / Q000378:metabolism*; D002874:Chromosome Mapping; D004721:Endoplasmic Reticulum / Q000378:metabolism*; D056625:Endosperm / Q000378:metabolism / Q000648:ultrastructure; D005455:Fluorescent Antibody Technique; D017343:Genes, Plant; D006056:Golgi Apparatus / Q000378:metabolism*; D042541:Intracellular Space / Q000378:metabolism; D008954:Models, Biological; D009154:Mutation / Q000235:genetics; D012275:Oryza / Q000235:genetics / Q000378:metabolism*; D010665:Phenylpropanolamine / Q000378:metabolism; D010940:Plant Proteins / Q000378:metabolism*; D021381:Protein Transport; D034443:RNA Transport; D018749:RNA, Plant / Q000378:metabolism
chemical_list: D000510:Alpha-Globulins; D010940:Plant Proteins; D018749:RNA, Plant; D010665:Phenylpropanolamine
keywords: Endoplasmic reticulum; Golgi transport; Intracellular transport; Proglutelin; Protein body; Storage protein