Characterizing the Interplay between Maize Retrotransposons and the Epigenome

In general, centromeres of higher eukaryotes are composed of large arrays of tandem repeats. In contrast, domestication of maize (Zea mays) has previously been found to be associated with frequent neocentromere formation and their invasion by centromere-targeting CR retrotransposons (PNAS 113(8):E987-96). This natural process provides an opportunity to study the changes in epigenetic markers as pericentric heterochromatin is converted to centromeric heterochromatin. Using the unique genetics of maize centromeres, we characterized the interaction between H2A.Z, which is usually associated with active genes, and cenH3, which is the key epigenetic marker required for kinetochore.

一般而言，高等真核生物的着丝粒（centromere）由大量串联重复序列（tandem repeats）构成。与之相对，既往研究表明玉米（Zea mays）的驯化过程与频繁的新着丝粒形成（neocentromere formation）、以及新着丝粒被靶向着丝粒的CR型反转录转座子（centromere-targeting CR retrotransposons）入侵密切相关（美国国家科学院院刊PNAS 113(8):E987-96）。这一天然过程为研究着丝粒旁异染色质（pericentric heterochromatin）向着丝粒异染色质（centromeric heterochromatin）转化过程中的表观遗传标记（epigenetic marker）变化提供了绝佳契机。本研究借助玉米着丝粒独特的遗传特征，对通常与活跃基因相关的组蛋白H2A.Z（H2A.Z），以及作为动粒（kinetochore）关键表观遗传标记的着丝粒特异性组蛋白H3（cenH3）之间的相互作用进行了系统表征。