Instituto de Bioquímica Vegetal y Fotosíntesis, Universidad de Sevilla - CSIC, 41092 Seville, Spain.
Nucleic Acids Res. 2011 Mar;39(6):2007-17. doi: 10.1093/nar/gkq1119. Epub 2010 Nov 10.
Telomere function is influenced by chromatin structure and organization, which usually involves epigenetic modifications. We describe here the chromatin structure of Arabidopsis thaliana telomeres. Based on the study of six different epigenetic marks we show that Arabidopsis telomeres exhibit euchromatic features. In contrast, subtelomeric regions and telomeric sequences present at interstitial chromosomal loci are heterochromatic. Histone methyltransferases and the chromatin remodeling protein DDM1 control subtelomeric heterochromatin formation. Whereas histone methyltransferases are required for histone H3K9(2Me) and non-CpG DNA methylation, DDM1 directs CpG methylation but not H3K9(2Me) or non-CpG methylation. These results argue that both kinds of proteins participate in different pathways to reinforce subtelomeric heterochromatin formation.
端粒功能受染色质结构和组织的影响，通常涉及表观遗传修饰。我们在这里描述拟南芥端粒的染色质结构。基于对六种不同表观遗传标记的研究，我们表明拟南芥端粒表现出常染色质特征。相比之下，着丝粒区域和位于染色体间位点的端粒序列是异染色质。组蛋白甲基转移酶和染色质重塑蛋白 DDM1 控制着丝粒异染色质的形成。虽然组蛋白甲基转移酶对于组蛋白 H3K9(2Me)和非 CpG DNA 甲基化是必需的，但 DDM1 指导 CpG 甲基化，但不指导 H3K9(2Me)或非 CpG 甲基化。这些结果表明，这两种蛋白参与不同的途径来加强着丝粒异染色质的形成。
