title: Identification of a novel plant MAR DNA binding protein localized on chromosomal surfaces.
abstract: We identified a novel nucleoplasm localized protein in Arabidopsis called AT-hook motif nuclear localized protein 1 (AHL1), which was isolated by visual screening of transformants using random GFP::cDNA fusions. AHL1 contains an AT-hook motif and unknown conserved PPC (plants and prokaryotes conserved) domain that includes a hydrophobic region. Approximately 30 paralogues were identified in the Arabidopsis genome. Proteins with PPC-like domains are found in Bacteria, Archaea and the plant kingdom, but in Bacteria and Archaea the PPC containing proteins of do not have an AT-hook motif. Thus, the PPC domain is evolutionary conserved and has a new function such as AT-rich DNA binding. AHL1 was mainly localized in the nucleoplasm, but little in the nucleolus and heterochromatic region, and was concentrated in the boundary region between euchromatin and heterochromatin. Biochemically, AHL1 was also found in the nuclear matrix fraction. In the M phase, AHL1 was localized on the chromosomal surface. The AT-hook motif was essential for matrix attachment region (MAR) binding, and the hydrophobic region of the PPC was indispensable for nuclear localization. Our results suggest that AHL1 is a novel plant MAR binding protein, which is related to the positioning of chromatin fibers in the nucleus by the presence of an AT-hook motif and PPC domain. In addition, AHL1 is located on the surface of chromosomes during mitosis.
authors.affiliation: Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1, Yamadaoka, Suita, Osaka, 565-0871, Japan.
authors.forename: Satoru
authors.initials: S
authors.lastname: Fujimoto
authors.forename: Sachihiro
authors.initials: S
authors.lastname: Matsunaga
authors.forename: Masataka
authors.initials: M
authors.lastname: Yonemura
authors.forename: Susumu
authors.initials: S
authors.lastname: Uchiyama
authors.forename: Takachika
authors.initials: T
authors.lastname: Azuma
authors.forename: Kiichi
authors.initials: K
authors.lastname: Fukui
mesh_terms: D000595:Amino Acid Sequence; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D001665:Binding Sites / Q000235:genetics; D002467:Cell Nucleus / Q000378:metabolism; D032461:Chromosomes, Plant / Q000378:metabolism*; D018076:DNA, Complementary / Q000235:genetics / Q000378:metabolism; D018744:DNA, Plant / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D057927:Hydrophobic and Hydrophilic Interactions; D007399:Interphase; D036961:Matrix Attachment Region Binding Proteins / Q000235:genetics* / Q000378:metabolism; D008856:Microscopy, Fluorescence; D008938:Mitosis; D008969:Molecular Sequence Data; D015530:Nuclear Matrix / Q000378:metabolism; D010802:Phylogeny; D018517:Plant Roots / Q000166:cytology / Q000235:genetics / Q000378:metabolism; D030821:Plants, Genetically Modified; D011485:Protein Binding; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid
chemical_list: C496143:AHL1 protein, Arabidopsis; D029681:Arabidopsis Proteins; D018076:DNA, Complementary; D018744:DNA, Plant; D004268:DNA-Binding Proteins; D036961:Matrix Attachment Region Binding Proteins; D011993:Recombinant Fusion Proteins; D049452:Green Fluorescent Proteins