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Ando S, Nomoto M, Iwakawa H, Vial-Pradel S, Luo L, Sasabe M, Ohbayashi I, Yamamoto KT, Tada Y, Sugiyama M, Machida Y, Kojima S, Machida C. Arabidopsis ASYMMETRIC LEAVES2 and Nucleolar Factors Are Coordinately Involved in the Perinucleolar Patterning of AS2 Bodies and Leaf Development. Plants (Basel) 2023; 12:3621. [PMID: 37896084 PMCID: PMC10610122 DOI: 10.3390/plants12203621] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2023] [Revised: 10/09/2023] [Accepted: 10/13/2023] [Indexed: 10/29/2023]
Abstract
Arabidopsis ASYMMETRIC LEAVES2 (AS2) plays a key role in the formation of flat symmetric leaves. AS2 represses the expression of the abaxial gene ETTIN/AUXIN RESPONSE FACTOR3 (ETT/ARF3). AS2 interacts in vitro with the CGCCGC sequence in ETT/ARF3 exon 1. In cells of leaf primordia, AS2 localizes at peripheral regions of the nucleolus as two AS2 bodies, which are partially overlapped with chromocenters that contain condensed 45S ribosomal DNA repeats. AS2 contains the AS2/LOB domain, which consists of three sequences conserved in the AS2/LOB family: the zinc finger (ZF) motif, the ICG sequence including the conserved glycine residue, and the LZL motif. AS2 and the genes NUCLEOLIN1 (NUC1), RNA HELICASE10 (RH10), and ROOT INITIATION DEFECTIVE2 (RID2) that encode nucleolar proteins coordinately act as repressors against the expression of ETT/ARF3. Here, we examined the formation and patterning of AS2 bodies made from as2 mutants with amino acid substitutions in the ZF motif and the ICG sequence in cells of cotyledons and leaf primordia. Our results showed that the amino acid residues next to the cysteine residues in the ZF motif were essential for both the formation of AS2 bodies and the interaction with ETT/ARF3 DNA. The conserved glycine residue in the ICG sequence was required for the formation of AS2 bodies, but not for the DNA interaction. We also examined the effects of nuc1, rh10, and rid2 mutations, which alter the metabolism of rRNA intermediates and the morphology of the nucleolus, and showed that more than two AS2 bodies were observed in the nucleolus and at its periphery. These results suggested that the patterning of AS2 bodies is tightly linked to the morphology and functions of the nucleolus and the development of flat symmetric leaves in plants.
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Affiliation(s)
- Sayuri Ando
- Graduate School of Bioscience and Biotechnology, Chubu University, Kasugai 487-8501, Japan; (S.A.); (H.I.); (S.V.-P.); (Y.M.)
| | - Mika Nomoto
- Division of Biological Science, Graduate School of Science, Nagoya University, Nagoya 464-8602, Japan; (M.N.); (L.L.); (Y.T.)
- Center for Gene Research, Nagoya University, Nagoya 464-8602, Japan
| | - Hidekazu Iwakawa
- Graduate School of Bioscience and Biotechnology, Chubu University, Kasugai 487-8501, Japan; (S.A.); (H.I.); (S.V.-P.); (Y.M.)
| | - Simon Vial-Pradel
- Graduate School of Bioscience and Biotechnology, Chubu University, Kasugai 487-8501, Japan; (S.A.); (H.I.); (S.V.-P.); (Y.M.)
| | - Lilan Luo
- Division of Biological Science, Graduate School of Science, Nagoya University, Nagoya 464-8602, Japan; (M.N.); (L.L.); (Y.T.)
| | - Michiko Sasabe
- Department of Biology, Faculty of Agriculture and Life Science, Hirosaki University, Bunkyo-cho, Hirosaki 036-8561, Japan;
| | - Iwai Ohbayashi
- Department of Life Sciences, National Cheng Kung University, Tainan City 701, Taiwan;
| | - Kotaro T. Yamamoto
- Division of Biological Sciences, Faculty of Science, Hokkaido University, Sapporo 060-0810, Japan
| | - Yasuomi Tada
- Division of Biological Science, Graduate School of Science, Nagoya University, Nagoya 464-8602, Japan; (M.N.); (L.L.); (Y.T.)
- Center for Gene Research, Nagoya University, Nagoya 464-8602, Japan
| | - Munetaka Sugiyama
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo 113-0033, Japan;
| | - Yasunori Machida
- Graduate School of Bioscience and Biotechnology, Chubu University, Kasugai 487-8501, Japan; (S.A.); (H.I.); (S.V.-P.); (Y.M.)
- Division of Biological Science, Graduate School of Science, Nagoya University, Nagoya 464-8602, Japan; (M.N.); (L.L.); (Y.T.)
| | - Shoko Kojima
- Graduate School of Bioscience and Biotechnology, Chubu University, Kasugai 487-8501, Japan; (S.A.); (H.I.); (S.V.-P.); (Y.M.)
| | - Chiyoko Machida
- Graduate School of Bioscience and Biotechnology, Chubu University, Kasugai 487-8501, Japan; (S.A.); (H.I.); (S.V.-P.); (Y.M.)
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Havlová K, Dvořáčková M, Peiro R, Abia D, Mozgová I, Vansáčová L, Gutierrez C, Fajkus J. Variation of 45S rDNA intergenic spacers in Arabidopsis thaliana. Plant Mol Biol 2016; 92:457-471. [PMID: 27531496 DOI: 10.1007/s11103-016-0524-1] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Accepted: 08/03/2016] [Indexed: 05/28/2023]
Abstract
Approximately seven hundred 45S rRNA genes (rDNA) in the Arabidopsis thaliana genome are organised in two 4 Mbp-long arrays of tandem repeats arranged in head-to-tail fashion separated by an intergenic spacer (IGS). These arrays make up 5 % of the A. thaliana genome. IGS are rapidly evolving sequences and frequent rearrangements inside the rDNA loci have generated considerable interspecific and even intra-individual variability which allows to distinguish among otherwise highly conserved rRNA genes. The IGS has not been comprehensively described despite its potential importance in regulation of rDNA transcription and replication. Here we describe the detailed sequence variation in the complete IGS of A. thaliana WT plants and provide the reference/consensus IGS sequence, as well as genomic DNA analysis. We further investigate mutants dysfunctional in chromatin assembly factor-1 (CAF-1) (fas1 and fas2 mutants), which are known to have a reduced number of rDNA copies, and plant lines with restored CAF-1 function (segregated from a fas1xfas2 genetic background) showing major rDNA rearrangements. The systematic rDNA loss in CAF-1 mutants leads to the decreased variability of the IGS and to the occurrence of distinct IGS variants. We present for the first time a comprehensive and representative set of complete IGS sequences, obtained by conventional cloning and by Pacific Biosciences sequencing. Our data expands the knowledge of the A. thaliana IGS sequence arrangement and variability, which has not been available in full and in detail until now. This is also the first study combining IGS sequencing data with RFLP analysis of genomic DNA.
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Affiliation(s)
- Kateřina Havlová
- Mendel Centre for Plant Genomics and Proteomics, CEITEC, Masaryk University, Kamenice 5, 62500, Brno, Czech Republic
| | - Martina Dvořáčková
- Mendel Centre for Plant Genomics and Proteomics, CEITEC, Masaryk University, Kamenice 5, 62500, Brno, Czech Republic.
- Institute of Biophysics ASCR, v.v.i., Královopolská 135, 61265, Brno, Czech Republic.
| | - Ramon Peiro
- Centro de Biologia Molecular Severo Ochoa, CSIC-UAM, Nicolas Cabrera 1, Madrid, 28049, Spain
| | - David Abia
- Centro de Biologia Molecular Severo Ochoa, CSIC-UAM, Nicolas Cabrera 1, Madrid, 28049, Spain
| | - Iva Mozgová
- Faculty of Science, Laboratory of Functional Genomics and Proteomics, National Centre for Biomolecular Research, Masaryk University, Kotlářská 2, 61137, Brno, Czech Republic
| | - Lenka Vansáčová
- Faculty of Science, Laboratory of Functional Genomics and Proteomics, National Centre for Biomolecular Research, Masaryk University, Kotlářská 2, 61137, Brno, Czech Republic
| | - Crisanto Gutierrez
- Centro de Biologia Molecular Severo Ochoa, CSIC-UAM, Nicolas Cabrera 1, Madrid, 28049, Spain
| | - Jiří Fajkus
- Mendel Centre for Plant Genomics and Proteomics, CEITEC, Masaryk University, Kamenice 5, 62500, Brno, Czech Republic.
- Faculty of Science, Laboratory of Functional Genomics and Proteomics, National Centre for Biomolecular Research, Masaryk University, Kotlářská 2, 61137, Brno, Czech Republic.
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