抄録
Regulation of ribosomal biogenesis strongly depends on the function of GTPases of YawG family members in eukaryotes, which are earmarked by a permutated order of GTPase motifs within the GTP-binding domain. The Nug protein, a member of YawG GTPases, is known to be associated with 60S ribosomal maturation in nucleolus and nucleus. Lack of understanding of plant Nug proteins in spite of their wide distribution in eukaryotes so far led us to characterize a rice nuclear GTPase, OsNug2 as a yeast Nug2 homolog on the molecular level. We showed that the OsNug2 exhibits a circularly permutated GTPase fold and an intrinsic GTPase activity. Complementation analysis using yeast Nug2 temperature-sensitive mutant cells demonstrated that the OsNug2 could replace them. We also provide evidence that OsNug2 localizes to the nucleus mediated by N-terminal OsNug2 domain. From these, we propose that rice nuclear GTPase, OsNug2 might play a role in 60S ribosomal maturation.
