Abstract：
Chemical modifications of DNA and histone proteins impact the organization of chromatin within the nucleus. Changes in these modifications, catalysed by different chromatin-modifying enzymes, influence chromatin organization, which in turn is thought to impact the spatial and temporal regulation of gene expression. While combinations of different histone modifications, the histone code, have been studied in several model species, we know very little about histone modifications in the fungal genus Aspergillus, whose members are generally well studied due to their importance as models in cell and molecular biology as well as their medical and biotechnological relevance. Here, we used phylogenetic analyses in 94 Aspergilli as well as other fungi to uncover the occurrence and evolutionary trajectories of enzymes and protein complexes with roles in chromatin modifications or regulation. We found that these enzymes and complexes are highly conserved in Aspergilli, pointing towards a complex repertoire of chromatin modifications. Nevertheless, we also observed few recent gene duplications or losses, highlighting Aspergillus species to further study the roles of specific chromatin modifications. SET7 (KMT6) and other components of PRC2 (Polycomb Repressive Complex 2), which is responsible for methylation on histone H3 at lysine 27 in many eukaryotes including fungi, are absent in Aspergilli as well as in closely related Penicillium species, suggesting that these lost the capacity for this histone modification. We corroborated our computational predictions by performing untargeted MS analysis of histone post-translational modifications in Aspergillus nidulans. This systematic analysis will pave the way for future research into the complexity of the histone code and its functional implications on genome architecture and gene regulation in fungi.
摘要：
DNA和组蛋白的化学修饰会影响核内染色质的组织。这些修改的变化，由不同的染色质修饰酶催化，影响染色质组织，这反过来被认为会影响基因表达的时空调控。虽然不同组蛋白修饰的组合，组蛋白密码,已经在几个模型物种中进行了研究，我们对曲霉菌属的组蛋白修饰知之甚少，由于其在细胞和分子生物学中作为模型的重要性以及其医学和生物技术相关性，其成员通常得到了很好的研究。这里,我们在94种曲霉和其他真菌中进行了系统发育分析，以揭示在染色质修饰或调节中起作用的酶和蛋白质复合物的发生和进化轨迹。我们发现这些酶和复合物在曲霉中高度保守，指向复杂的染色质修饰库。然而，我们还观察到最近很少有基因重复或丢失，突出曲霉属物种以进一步研究特定染色质修饰的作用。SET7（KMT6）和PRC2（多梳抑制复合物2）的其他成分，在包括真菌在内的许多真核生物中，赖氨酸27处组蛋白H3的甲基化负责，在曲霉属以及密切相关的青霉属物种中都不存在，表明这些失去了这种组蛋白修饰的能力。我们通过对构巢曲霉中的组蛋白翻译后修饰进行非靶向MS分析来证实我们的计算预测。这种系统分析将为将来研究组蛋白密码的复杂性及其对真菌基因组结构和基因调控的功能影响铺平道路。
