title: ZmMBD101 is a DNA-binding protein that maintains Mutator elements chromatin in a repressive state in maize.
abstract: In maize (Zea mays), as well as in other crops, transposable elements (TEs) constitute a great proportion of the genome. Chromatin modifications play a vital role in establishing transposon silencing and perpetuating the acquired repressive state. Nucleosomes associated with TEs are enriched for dimethylation of histone H3 at lysine 9 and 27 (H3K9me2 and H3K27me2, respectively), signals of repressive chromatin. Here, we describe a chromatin protein, ZmMBD101, involved in the regulation of Mutator (Mu) genes in maize. ZmMBD101 is localized to the nucleus and contains a methyl-CpG-binding domain (MBD) and a zinc finger CW (CW) domain. Transgenic lines with reduced levels of ZmMBD101 transcript present enhanced induction of Mu genes when plants are irradiated with UV-B. Chromatin immunoprecipitation analysis with H3K9me2 and H3K27me2 antibodies indicated that ZmMBD101 is required to maintain the levels of these histone repressive marks at Mu terminal inverted repeats (TIRs) under UV-B conditions. Although Mutator inactivity is associated with DNA methylation, cytosine methylation at Mu TIRs is not affected in ZmMBD101 deficient plants. Several plant proteins are predicted to share the simple CW-MBD domain architecture present in ZmMBD101. We hypothesize that plant CW-MBD proteins may also function to protect plant genomes from deleterious transposition.
authors.affiliation: Centro de Estudios Fotosintéticos y Bioquímicos (CEFOBI-CONICET), Universidad Nacional de Rosario, Suipacha 531, 2000, Rosario, Argentina.
authors.forename: Julia I
authors.initials: JI
authors.lastname: Questa
authors.affiliation: Centro de Estudios Fotosintéticos y Bioquímicos (CEFOBI-CONICET), Universidad Nacional de Rosario, Suipacha 531, 2000, Rosario, Argentina.
authors.forename: Sebastián P
authors.initials: SP
authors.lastname: Rius
authors.affiliation: Centro de Estudios Fotosintéticos y Bioquímicos (CEFOBI-CONICET), Universidad Nacional de Rosario, Suipacha 531, 2000, Rosario, Argentina.
authors.forename: Romina
authors.initials: R
authors.lastname: Casadevall
authors.affiliation: Centro de Estudios Fotosintéticos y Bioquímicos (CEFOBI-CONICET), Universidad Nacional de Rosario, Suipacha 531, 2000, Rosario, Argentina.
authors.forename: Paula
authors.initials: P
authors.lastname: Casati
mesh_terms: D017360:Arabidopsis / Q000166:cytology / Q000235:genetics / Q000378:metabolism / Q000528:radiation effects; D002467:Cell Nucleus / Q000378:metabolism; D002843:Chromatin / Q000235:genetics; D019175:DNA Methylation; D004251:DNA Transposable Elements / Q000235:genetics*; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D044127:Epigenesis, Genetic; D018506:Gene Expression Regulation, Plant; D017930:Genes, Reporter; D018745:Genome, Plant / Q000235:genetics*; D006657:Histones / Q000235:genetics / Q000378:metabolism; D009154:Mutation; D010802:Phylogeny; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D030821:Plants, Genetically Modified; D021381:Protein Transport; D034622:RNA Interference; D011993:Recombinant Fusion Proteins; D014466:Ultraviolet Rays; D003313:Zea mays / Q000166:cytology / Q000235:genetics* / Q000378:metabolism / Q000528:radiation effects
chemical_list: D002843:Chromatin; D004251:DNA Transposable Elements; D004268:DNA-Binding Proteins; D006657:Histones; D010940:Plant Proteins; D011993:Recombinant Fusion Proteins
keywords: UV-B; methyl-CpG-binding domain proteins; transposon elements