title: The plant-specific family of DNA-binding proteins containing three HMG-box domains interacts with mitotic and meiotic chromosomes.
abstract: • The high mobility group (HMG)-box represents a DNA-binding domain that is found in various eukaryotic DNA-interacting proteins. Proteins that contain three copies of the HMG-box domain, termed 3 × HMG-box proteins, appear to be specific to plants. The Arabidopsis genome encodes two 3 × HMG-box proteins that were studied here. • DNA interactions were examined using electrophoretic mobility shift assays, whereas expression, subcellular localization and chromosome association were mainly analysed by different types of fluorescence microscopy. • The 3 × HMG-box proteins bind structure specifically to DNA, display DNA bending activity and, in addition to the three HMG-box domains, the basic N-terminal domain contributes to DNA binding. The expression of the two Arabidopsis genes encoding 3 × HMG-box proteins is linked to cell proliferation. In synchronized cells, expression is cell cycle dependent and peaks in cells undergoing mitosis. 3 × HMG-box proteins are excluded from the nuclei of interphase cells and localize to the cytosol, but, during mitosis, they associate with condensed chromosomes. The 3 × HMG-box2 protein generally associates with mitotic chromosomes, while 3 × HMG-box1 is detected specifically at 45S rDNA loci. • In addition to mitotic chromosomes the 3 × HMG-box proteins associate with meiotic chromosomes, suggesting that they are involved in a general process of chromosome function related to cell division, such as chromosome condensation and/or segregation.
authors.affiliation: Cell Biology and Plant Biochemistry, Regensburg University, Regensburg, Germany.
authors.forename: Dorthe S
authors.initials: DS
authors.lastname: Pedersen
authors.forename: Frederik
authors.initials: F
authors.lastname: Coppens
authors.forename: Lu
authors.initials: L
authors.lastname: Ma
authors.forename: Martin
authors.initials: M
authors.lastname: Antosch
authors.forename: Barbara
authors.initials: B
authors.lastname: Marktl
authors.forename: Thomas
authors.initials: T
authors.lastname: Merkle
authors.forename: Gerrit T S
authors.initials: GT
authors.lastname: Beemster
authors.forename: Andreas
authors.initials: A
authors.lastname: Houben
authors.forename: Klaus D
authors.initials: KD
authors.lastname: Grasser
mesh_terms: D017360:Arabidopsis / Q000166:cytology / Q000235:genetics / Q000378:metabolism*; D049109:Cell Proliferation; D032461:Chromosomes, Plant / Q000378:metabolism*; D018744:DNA, Plant / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant / Q000235:genetics; D024742:HMG-Box Domains; D008540:Meiosis; D008938:Mitosis; D030821:Plants, Genetically Modified; D011401:Promoter Regions, Genetic / Q000235:genetics; D011485:Protein Binding; D021381:Protein Transport; D011994:Recombinant Proteins / Q000378:metabolism; D013045:Species Specificity; D013347:Subcellular Fractions / Q000378:metabolism
chemical_list: D018744:DNA, Plant; D004268:DNA-Binding Proteins; D011994:Recombinant Proteins