A Matrix Protein Silences Transposons and Repeats through Interaction with Retinoblastoma-Associated Proteins

• Published in: Current biology 2013-02, Vol.23 (4), p.345-350
• Main Authors: Xu, Yifeng, Wang, Yizhong, Stroud, Hume, Gu, Xiaofeng, Sun, Bo, Gan, Eng-Seng, Ng, Kian-Hong, Jacobsen, Steven E., He, Yuehui, Ito, Toshiro
• Format: Article
• Language: English
• Subjects: acetylation; Arabidopsis; Arabidopsis - genetics; Chromatin; Chromatin - genetics; Chromatin - metabolism; Deacetylation; Derepression; DNA Methylation; DNA Transposable Elements - genetics; DNA-binding domains; DNA-Binding Proteins - genetics; DNA-Binding Proteins - metabolism; Epigenesis, Genetic; epigenetics; Flowering; Gene expression; Gene Expression Regulation, Plant; genes; Genomes; genomics; Histones; loci; Lysine; matrix protein; Methylation; Mutation; nuclear matrix; Nuclear Matrix-Associated Proteins - genetics; Regulatory sequences; Repeated DNA sequences; Repressors; Retinoblastoma Binding Proteins - metabolism; retinoblastoma-associated protein; RNA Interference; RNA, Small Interfering; Transposition; Transposons
• ISSN: 0960-9822; 1879-0445
• DOI: 10.1016/j.cub.2013.01.030

Epigenetic regulation helps to maintain genomic integrity by suppressing transposable elements (TEs) and also controls key developmental processes, such as flowering time [1–3]. To prevent TEs from causing rearrangements and mutations, TE and TE-like repetitive DNA sequences are usually methylated, whereas histones are hypoacetylated and methylated on specific residues (e.g., H3 lysine 9 dimethylation [H3K9me2]) [4, 5]. TEs and repeats can also attenuate gene expression [2, 6–8]. However, how various histone modifiers are recruited to target loci is not well understood. Here we show that knockdown of the nuclear matrix protein with AT-hook DNA binding motifs [9–11] TRANSPOSABLE ELEMENT SILENCING VIA AT-HOOK (TEK) in Arabidopsis Landsberg erecta results in robust activation of various TEs, the TE-like repeat-containing floral repressor genes FLOWERING LOCUS C (FLC) and FWA [1, 2, 12]. This derepression is associated with chromatin conformational changes, increased histone acetylation, reduced H3K9me2, and even TE transposition. TEK directly binds to an FLC-repressive regulatory region and the silencing repeats of FWA and associates with Arabidopsis homologs of the Retinoblastoma-associated protein 46/48, FVE and MSI5, which mediate histone deacetylation [13, 14]. We propose that the nuclear matrix protein TEK acts in the maintenance of genome integrity by silencing TE and repeat-containing genes. [Display omitted] ► The Arabidopsis matrix protein TEK silences transposons and repeat-containing genes ► Binding of TEK on targets affects chromatin conformation and histone modifications ► TEK protein associates with FVE/MSI5-containing histone deacetylation complex ► TEK directs repressive modification as a key structural component in gene silencing