title: Histone deacetylases and ASYMMETRIC LEAVES2 are involved in the establishment of polarity in leaves of Arabidopsis.
abstract: We show that two Arabidopsis thaliana genes for histone deacetylases (HDACs), HDT1/HD2A and HDT2/HD2B, are required to establish leaf polarity in the presence of mutant ASYMMETRIC LEAVES2 (AS2) or AS1. Treatment of as1 or as2 plants with inhibitors of HDACs resulted in abaxialized filamentous leaves and aberrant distribution of microRNA165 and/or microRNA166 (miR165/166) in leaves. Knockdown mutations of these two HDACs by RNA interference resulted in phenotypes like those observed in the as2 background. Nuclear localization of overproduced AS2 resulted in decreased levels of mature miR165/166 in leaves. This abnormality was abolished by HDAC inhibitors, suggesting that HDACs are required for AS2 action. A loss-of-function mutation in HASTY, encoding a positive regulator of miRNA levels, and a gain-of-function mutation in PHABULOSA, encoding a determinant of adaxialization, suppressed the generation of abaxialized filamentous leaves by inhibition of HDACs in the as1 or as2 background. AS2 and AS1 were colocalized in subnuclear bodies adjacent to the nucleolus where HDT1/HD2A and HDT2/HD2B were also found. Our results suggest that these HDACs and both AS2 and AS1 act independently to control levels and/or patterns of miR165/166 distribution and the development of adaxial-abaxial leaf polarity and that there may be interactions between HDACs and AS2 (AS1) in the generation of those miRNAs.
authors.affiliation: Division of Biological Sciences, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan.
authors.forename: Yoshihisa
authors.initials: Y
authors.lastname: Ueno
authors.forename: Takaaki
authors.initials: T
authors.lastname: Ishikawa
authors.forename: Keiro
authors.initials: K
authors.lastname: Watanabe
authors.forename: Shinji
authors.initials: S
authors.lastname: Terakura
authors.forename: Hidekazu
authors.initials: H
authors.lastname: Iwakawa
authors.forename: Kiyotaka
authors.initials: K
authors.lastname: Okada
authors.forename: Chiyoko
authors.initials: C
authors.lastname: Machida
authors.forename: Yasunori
authors.initials: Y
authors.lastname: Machida
mesh_terms: D017360:Arabidopsis / Q000033:anatomy & histology / Q000235:genetics / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D002467:Cell Nucleus / Q000378:metabolism; D006655:Histone Deacetylases / Q000235:genetics / Q000378:metabolism*; D035683:MicroRNAs / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D018515:Plant Leaves / Q000033:anatomy & histology / Q000502:physiology; D030821:Plants, Genetically Modified; D034622:RNA Interference; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
chemical_list: C463739:AS2 protein, Arabidopsis; C456239:ASYMMETRIC LEAVES1 protein, Arabidopsis; D029681:Arabidopsis Proteins; D035683:MicroRNAs; D014157:Transcription Factors; C521257:HDT1 protein, Arabidopsis; C521258:HDT2 protein, Arabidopsis; D006655:Histone Deacetylases