title: HASTY, the Arabidopsis ortholog of exportin 5/MSN5, regulates phase change and morphogenesis.
abstract: Loss-of-function mutations of HASTY (HST) affect many different processes in Arabidopsis development. In addition to reducing the size of both roots and lateral organs of the shoot, hst mutations affect the size of the shoot apical meristem, accelerate vegetative phase change, delay floral induction under short days, adaxialize leaves and carpels, disrupt the phyllotaxis of the inflorescence, and reduce fertility. Double mutant analysis suggests that HST acts in parallel to SQUINT in the regulation of phase change and in parallel to KANADI in the regulation of leaf polarity. Positional cloning demonstrated that HST is the Arabidopsis ortholog of the importin beta-like nucleocytoplasmic transport receptors exportin 5 in mammals and MSN5 in yeast. Consistent with a potential role in nucleocytoplasmic transport, we found that HST interacts with RAN1 in a yeast two-hybrid assay and that a HST-GUS fusion protein is located at the periphery of the nucleus. HST is one of at least 17 members of the importin-beta family in Arabidopsis and is the first member of this family shown to have an essential function in plants. The hst loss-of-function phenotype suggests that this protein regulates the nucleocytoplasmic transport of molecules involved in several different morphogenetic pathways, as well as molecules generally required for root and shoot growth.
authors.affiliation: Department of Biology, University of Pennsylvania, Philadelphia, PA 19104-6018, USA.
authors.forename: Krista M
authors.initials: KM
authors.lastname: Bollman
authors.forename: Milo J
authors.initials: MJ
authors.lastname: Aukerman
authors.forename: Mee-Yeon
authors.initials: MY
authors.lastname: Park
authors.forename: Christine
authors.initials: C
authors.lastname: Hunter
authors.forename: Tanya Z
authors.initials: TZ
authors.lastname: Berardini
authors.forename: R Scott
authors.initials: RS
authors.lastname: Poethig
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D017360:Arabidopsis / Q000033:anatomy & histology / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000737:chemistry / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D017343:Genes, Plant; D006801:Humans; D028884:Karyopherins / Q000737:chemistry / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D009024:Morphogenesis; D055456:Nodal Signaling Ligands; D010641:Phenotype; D017440:Photoperiod; D010802:Phylogeny; D030821:Plants, Genetically Modified; D016415:Sequence Alignment; D016212:Transforming Growth Factor beta / Q000378:metabolism; D020798:Two-Hybrid System Techniques; D029961:Zebrafish Proteins; D020931:ran GTP-Binding Protein / Q000235:genetics / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; C474286:HASTY protein, Arabidopsis; D028884:Karyopherins; D055456:Nodal Signaling Ligands; D016212:Transforming Growth Factor beta; C446511:XPO5 protein, human; D029961:Zebrafish Proteins; C485171:ndr1 protein, zebrafish; D020931:ran GTP-Binding Protein