title: The nucleolar GTPase nucleostemin-like 1 plays a role in plant growth and senescence by modulating ribosome biogenesis.
abstract: Nucleostemin is a nucleolar GTP-binding protein that is involved in stem cell proliferation, embryonic development, and ribosome biogenesis in mammals. Plant nucleostemin-like 1 (NSN1) plays a role in embryogenesis, and apical and floral meristem development. In this study, a nucleolar function of NSN1 in the regulation of ribosome biogenesis was identified. Green fluorescent protein (GFP)-fused NSN1 localized to the nucleolus, which was primarily determined by its N-terminal domain. Recombinant NSN1 and its N-terminal domain (NSN1-N) bound to RNA in vitro. Recombinant NSN1 expressed GTPase activity in vitro. NSN1 silencing in Arabidopsis thaliana and Nicotiana benthamiana led to growth retardation and premature senescence. NSN1 interacted with Pescadillo and EBNA1 binding protein 2 (EBP2), which are nucleolar proteins involved in ribosome biogenesis, and with several ribosomal proteins. NSN1, NSN1-N, and EBP2 co-fractionated primarily with the 60S ribosomal large subunit in vivo. Depletion of NSN1 delayed 25S rRNA maturation and biogenesis of the 60S ribosome subunit, and repressed global translation. NSN1-deficient plants exhibited premature leaf senescence, excessive accumulation of reactive oxygen species, and senescence-related gene expression. Taken together, these results suggest that NSN1 plays a crucial role in plant growth and senescence by modulating ribosome biogenesis.
authors.affiliation: Department of Systems Biology, Yonsei University, Seoul 120-749, Korea.
authors.forename: Young
authors.initials: Y
authors.lastname: Jeon
authors.affiliation: Department of Systems Biology, Yonsei University, Seoul 120-749, Korea.
authors.forename: Yong-Joon
authors.initials: YJ
authors.lastname: Park
authors.affiliation: Department of Systems Biology, Yonsei University, Seoul 120-749, Korea.
authors.forename: Hui Kyung
authors.initials: HK
authors.lastname: Cho
authors.affiliation: Department of Plant Biotechnology, College of Agriculture and Life Sciences, Chonnam National University, Gwangju 500-757, Korea.
authors.forename: Hyun Ju
authors.initials: HJ
authors.lastname: Jung
authors.affiliation: Department of Energy Science, Sungkyunkwan University, Suwon 440-746, Korea.
authors.forename: Tae-Kyu
authors.initials: TK
authors.lastname: Ahn
authors.affiliation: Department of Plant Biotechnology, College of Agriculture and Life Sciences, Chonnam National University, Gwangju 500-757, Korea.
authors.forename: Hunseung
authors.initials: H
authors.lastname: Kang
authors.affiliation: Department of Systems Biology, Yonsei University, Seoul 120-749, Korea hspai@yonsei.ac.kr.
authors.forename: Hyun-Sook
authors.initials: HS
authors.lastname: Pai
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D002466:Cell Nucleolus / Q000235:genetics / Q000378:metabolism; D019204:GTP-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D001678:Organelle Biogenesis; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D012270:Ribosomes / Q000502:physiology*; D014026:Nicotiana / Q000235:genetics / Q000502:physiology*
chemical_list: D029681:Arabidopsis Proteins; D010940:Plant Proteins; D019204:GTP-Binding Proteins; C569940:NSN1 protein, Arabidopsis
keywords: Delayed 25S rRNA maturation; GTPase activity; RNA binding activity; nucleolar localization; premature senescence; suppressed translation.