Biochemical characterization of the epigenome.

由我们的基因及其调控元件携带的遗传信息有助于所有活着的有机体的正常发育。尽管这种遗传密码很重要，但众所周知，另一层信息也是至关重要的。事实上，表观遗传信息被定义为不依赖于潜在DNA序列的可遗传信息，最近已经作为许多生物过程的主要调节因素浮出水面。DNA支架蛋白，如组蛋白，可以被化学修饰，这种共价改变可以触发特定的分子信号，这些发现是解开一个复杂、错综复杂的新密码的基石：组蛋白密码。组蛋白的修饰现在被认为携带着对许多分子事件至关重要的关键信息，包括基因转录、蛋白质翻译、DNA修复等许多其他分子事件。在这些共价修饰中，赖氨酸残基的甲基化是组蛋白最显著的变化之一。然而，尽管它们在细胞核中起着关键作用，但蛋白质赖氨酸甲基转移酶(MTS)控制组蛋白底物识别和甲基化的机制还需要进一步研究。我们关注植物PKMT的努力也是因为最近的发现表明，植物PKMT在植物的开花和生长中发挥关键作用；这增加了我们的发现可能对农业产生重要影响的希望。

The genetic information, which is carried by our genes and their regulatory elements, contribute to the proper development of all living organisms. Despite the importance of this genetic code, an additional layer of information is also known to be vital. In fact, epigenetic information, which is defined as heritable information that do not depend on the underlying DNA sequence, has recently surfaced as a master regulator of many biological processes. The discoveries that DNA scaffolding proteins, such as histones, could be chemically modified and that such covalent alterations could trigger specific molecular signals, have been cornerstone in unraveling a complex, intricate and new code: the histone code. Modifications of histone is now known to carry critical information vital for many molecular events including gene transcription, protein translation, DNA repair and many others. Among those covalent modifications, methylation of lysine residues is amongst the most prominent alteration of histone proteins. However, despite their critical roles in the nucleus, the mechanisms controlling histone substrates recognition and methylation by protein lysine methyltransferases (MTs) require further investigation. Our endeavors to focus on plant PKMT is also motivated by recent findings showing that plant PKMTs play pivotal roles in plant floraison and growth; raising the hope that our findings may have important impact in agriculture.