title: Arabidopsis TRANSCURVATA1 encodes NUP58, a component of the nucleopore central channel.
abstract: The selective trafficking of proteins and RNAs through the nuclear envelope regulates nuclear-cytoplasmic segregation of macromolecules and is mediated by nucleopore complexes (NPCs), which consist of about 400 nucleoporins (Nups) of about 30 types. Extensive studies of nucleoporin function in yeast and vertebrates showed that Nups function in nucleocytoplasmic trafficking and other processes. However, limited studies of plant Nups have identified only a few mutations, which cause pleiotropic phenotypes including reduced growth and early flowering. Here, we describe loss-of-function alleles of Arabidopsis TRANSCURVATA1 (TCU1); these mutations cause increased hypocotyl and petiole length, reticulate and asymmetrically epinastic leaf laminae of reduced size, and early flowering. TCU1 is transcribed in all of the organs and tissues examined, and encodes the putative ortholog of yeast and vertebrate Nup58, a nucleoporin of the Nup62 subcomplex. Nup58 forms the central channel of the NPC and acts directly in translocation of proteins through the nuclear envelope in yeast and vertebrates. Yeast two-hybrid (Y2H) assays identified physical interactions between TCU1/NUP58 and 34 proteins, including nucleoporins, SCF (Skp1/Cul1/F-box) ubiquitin ligase complex components and other nucleoplasm proteins. Genetic interactions were also found between TCU1 and genes encoding nucleoporins, soluble nuclear transport receptors and components of the ubiquitin-proteasome and auxin signaling pathways. These genetic and physical interactions indicate that TCU1/NUP58 is a member of the Nup62 subcomplex of the Arabidopsis NPC. Our findings also suggest regulatory roles for TCU1/NUP58 beyond its function in nucleocytoplasmic trafficking, a hypothesis that is supported by the Y2H and genetic interactions that we observed.
authors.affiliation: Instituto de Bioingeniería, Universidad Miguel Hernández, Campus de Elche, Elche, Spain.
authors.forename: Almudena
authors.initials: A
authors.lastname: Ferrández-Ayela
authors.forename: María Magdalena
authors.initials: MM
authors.lastname: Alonso-Peral
authors.forename: Ana Belén
authors.initials: AB
authors.lastname: Sánchez-García
authors.forename: Rosa
authors.initials: R
authors.lastname: Micol-Ponce
authors.forename: José Manuel
authors.initials: JM
authors.lastname: Pérez-Pérez
authors.forename: José Luis
authors.initials: JL
authors.lastname: Micol
authors.forename: María Rosa
authors.initials: MR
authors.lastname: Ponce
mesh_terms: D021581:Active Transport, Cell Nucleus / Q000235:genetics; D000483:Alleles; D000818:Animals; D017360:Arabidopsis / Q000235:genetics* / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D002467:Cell Nucleus / Q000235:genetics / Q000378:metabolism; D003593:Cytoplasm / Q000235:genetics / Q000378:metabolism; D035264:Flowers / Q000235:genetics / Q000378:metabolism; D018546:Hypocotyl / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D022022:Nuclear Pore / Q000235:genetics* / Q000378:metabolism; D028861:Nuclear Pore Complex Proteins / Q000235:genetics* / Q000378:metabolism; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D018515:Plant Leaves / Q000235:genetics / Q000378:metabolism; D021381:Protein Transport / Q000235:genetics; D020798:Two-Hybrid System Techniques; D043743:Ubiquitin-Protein Ligase Complexes / Q000235:genetics / Q000378:metabolism; D014714:Vertebrates / Q000235:genetics / Q000378:metabolism; D015003:Yeasts / Q000235:genetics / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; D028861:Nuclear Pore Complex Proteins; D009687:Nuclear Proteins; D043743:Ubiquitin-Protein Ligase Complexes