title: SHA1, a novel RING finger protein, functions in shoot apical meristem maintenance in Arabidopsis.
abstract: Post-embryonic plant growth is dependent on a functional shoot apical meristem (SAM) that provides cells for continuous development of new aerial organs. However, how the SAM is dynamically maintained during vegetative development remains largely unclear. We report here the characterization of a new SAM maintenance mutant, sha1-1 (shoot apical meristem arrest 1-1), that shows a primary SAM-deficient phenotype at the adult stage. The SHA1 gene encodes a novel RING finger protein, and is expressed most intensely in the shoot apex. We show that, in the sha1-1 mutant, the primary SAM develops normally during the juvenile vegetative stage, but cell layer structure becomes disorganized after entering the adult vegetative stage, resulting in a dysfunctional SAM that cannot initiate floral primordia. The sha1-1 SAM terminates completely at the stage when the wild-type begins to bolt, producing adult plants with a primary inflorescence-deficient phenotype. These observations indicate that SHA1, a putative E3 ligase, is required for post-embryonic SAM maintenance by controlling proper cellular organization.
authors.affiliation: Faculty of Advanced Life Science and Graduate School of Life Science, Hokkaido University, Kita-ku N10-W8, Sapporo 060-0810, Japan.
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Sonoda
authors.forename: Shan-Guo
authors.initials: SG
authors.lastname: Yao
authors.forename: Kaori
authors.initials: K
authors.lastname: Sako
authors.forename: Takeo
authors.initials: T
authors.lastname: Sato
authors.forename: Wataru
authors.initials: W
authors.lastname: Kato
authors.forename: Masa-aki
authors.initials: MA
authors.lastname: Ohto
authors.forename: Takanari
authors.initials: T
authors.lastname: Ichikawa
authors.forename: Minami
authors.initials: M
authors.lastname: Matsui
authors.forename: Junji
authors.initials: J
authors.lastname: Yamaguchi
authors.forename: Akira
authors.initials: A
authors.lastname: Ikeda
mesh_terms: D000595:Amino Acid Sequence; D029681:Arabidopsis Proteins / Q000235:genetics / Q000502:physiology*; D001483:Base Sequence; D017931:DNA Primers; D004843:Epistasis, Genetic; D018519:Meristem / Q000254:growth & development*; D008855:Microscopy, Electron, Scanning; D008969:Molecular Sequence Data; D017386:Sequence Homology, Amino Acid
chemical_list: D029681:Arabidopsis Proteins; D017931:DNA Primers