title: Proteomic analysis of rice endosperm cells in response to expression of hGM-CSF.
abstract: The accumulation of significant levels of transgenic products in plant cells is required not only for crop improvement, but also for molecular pharming. However, knowledge about the fate of transgenic products and endogenous proteins in grain cells is lacking. Here, we utilized a quantitative mass spectrometry-based proteomic approach for comparative analysis of expression profiles of transgenic rice endosperm cells in response to expression of a recombinant pharmaceutical protein, human granulocyte-macrophage colony stimulation factor (hGM-CSF). This study provided the first available evidence concerning the fate of exogenous and endogenous proteins in grain cells. Among 1883 identified proteins with a false positive rate of 5%, 103 displayed significant changes (p-value < 0.05) between the transgenic and the wild-type endosperm cells. Notably, endogenous storage proteins and most carbohydrate metabolism-related proteins were down-regulated, while 26S proteasome-related proteins and chaperones were up-regulated in the transgenic rice endosperm. Furthermore, it was observed that expression of hGM-CSF induced endoplasmic reticulum stress and activated the ubiquitin/26S-proteasome pathway, which led to ubiquitination of this foreign gene product in the transgenic rice endosperm.
authors.affiliation: Department of Genetics, College of Life Sciences, Wuhan University, 430072, People's Republic of China.
authors.forename: Junling
authors.initials: J
authors.lastname: Luo
authors.forename: Tingting
authors.initials: T
authors.lastname: Ning
authors.forename: Yunfang
authors.initials: Y
authors.lastname: Sun
authors.forename: Jinghua
authors.initials: J
authors.lastname: Zhu
authors.forename: Yingguo
authors.initials: Y
authors.lastname: Zhu
authors.forename: Qishan
authors.initials: Q
authors.lastname: Lin
authors.forename: Daichang
authors.initials: D
authors.lastname: Yang
mesh_terms: D004721:Endoplasmic Reticulum / Q000378:metabolism; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D012275:Oryza / Q000737:chemistry / Q000166:cytology; D010940:Plant Proteins / Q000032:analysis* / Q000235:genetics; D030821:Plants, Genetically Modified; D046988:Proteasome Endopeptidase Complex / Q000378:metabolism; D020543:Proteome / Q000032:analysis*; D011994:Recombinant Proteins; D025801:Ubiquitin / Q000378:metabolism
chemical_list: D010940:Plant Proteins; D020543:Proteome; D011994:Recombinant Proteins; D025801:Ubiquitin; D016178:Granulocyte-Macrophage Colony-Stimulating Factor; D046988:Proteasome Endopeptidase Complex