title: Nuclear/nucleolar GTPase 2 proteins as a subfamily of YlqF/YawG GTPases function in pre-60S ribosomal subunit maturation of mono- and dicotyledonous plants.
abstract: The YlqF/YawG families are important GTPases involved in ribosome biogenesis, cell proliferation, or cell growth, however, no plant homologs have yet to be characterized. Here we isolated rice (Oryza sativa) and Arabidopsis nuclear/nucleolar GTPase 2 (OsNug2 and AtNug2, respectively) that belong to the YawG subfamily and characterized them for pre-60S ribosomal subunit maturation. They showed typical intrinsic YlqF/YawG family GTPase activities in bacteria and yeasts with k(cat) values 0.12 ± 0.007 min(-1) (n = 6) and 0.087 ± 0.002 min(-1) (n = 4), respectively, and addition of 60S ribosomal subunits stimulated their activities in vitro. In addition, OsNug2 rescued the lethality of the yeast nug2 null mutant through recovery of 25S pre-rRNA processing. By yeast two-hybrid screening five clones, including a putative one of 60S ribosomal proteins, OsL10a, were isolated. Subcellular localization and pulldown assays resulted in that the N-terminal region of OsNug2 is sufficient for nucleolar/nuclear targeting and association with OsL10a. OsNug2 is physically associated with pre-60S ribosomal complexes highly enriched in the 25S, 5.8S, and 5S rRNA, and its interaction was stimulated by exogenous GTP. Furthermore, the AtNug2 knockdown mutant constructed by the RNAi method showed defective growth on the medium containing cycloheximide. Expression pattern analysis revealed that the distribution of AtNug2 mainly in the meristematic region underlies its potential role in active plant growth. Finally, it is concluded that Nug2/Nog2p GTPase from mono- and didicotyledonous plants is linked to the pre-60S ribosome complex and actively processed 27S into 25S during the ribosomal large subunit maturation process, i.e. prior to export to the cytoplasm.
authors.affiliation: From the Division of Applied Life Sciences (BK21), Graduate School of Gyeongsang National University, Jinju 660-701, Korea.
authors.forename: Chak Han
authors.initials: CH
authors.lastname: Im
authors.affiliation: From the Division of Applied Life Sciences (BK21), Graduate School of Gyeongsang National University, Jinju 660-701, Korea.
authors.forename: Sung Min
authors.initials: SM
authors.lastname: Hwang
authors.affiliation: From the Division of Applied Life Sciences (BK21), Graduate School of Gyeongsang National University, Jinju 660-701, Korea.
authors.forename: Young Sim
authors.initials: YS
authors.lastname: Son
authors.affiliation: From the Division of Applied Life Sciences (BK21), Graduate School of Gyeongsang National University, Jinju 660-701, Korea.
authors.forename: Jae Bok
authors.initials: JB
authors.lastname: Heo
authors.affiliation: From the Division of Applied Life Sciences (BK21), Graduate School of Gyeongsang National University, Jinju 660-701, Korea.
authors.forename: Woo Young
authors.initials: WY
authors.lastname: Bang
authors.affiliation: the Graduate School of Biostudies, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan, and.
authors.forename: I Nengah
authors.initials: IN
authors.lastname: Suwastika
authors.affiliation: the Graduate School of Human and Environmental Sciences, Kyoto Prefectural University, Shimogamo, Sakyo-ku, Kyoto 606-8522, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Shiina
authors.affiliation: From the Division of Applied Life Sciences (BK21), Graduate School of Gyeongsang National University, Jinju 660-701, Korea,. Electronic address: jdbahk@gnu.ac.kr.
authors.forename: Jeong Dong
authors.initials: JD
authors.lastname: Bahk
mesh_terms: D021581:Active Transport, Cell Nucleus / Q000502:physiology; D017360:Arabidopsis / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development; D002467:Cell Nucleus / Q000201:enzymology* / Q000235:genetics; D020558:GTP Phosphohydrolases / Q000235:genetics / Q000378:metabolism*; D015971:Gene Expression Regulation, Enzymologic / Q000502:physiology; D018506:Gene Expression Regulation, Plant / Q000502:physiology; D005816:Genetic Complementation Test; D018519:Meristem / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D012275:Oryza / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D018749:RNA, Plant / Q000235:genetics / Q000378:metabolism; D012335:RNA, Ribosomal / Q000235:genetics / Q000378:metabolism; D054683:Ribosome Subunits, Large, Eukaryotic / Q000235:genetics / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism
chemical_list: D009687:Nuclear Proteins; D010940:Plant Proteins; D018749:RNA, Plant; D012335:RNA, Ribosomal; D020558:GTP Phosphohydrolases