Charactorization of post-translational modifications of histone H2B-variants isolated from Arabidopsis thaliana
Charactorization of post-translational modifications of histone H2B-variants isolated from Arabidopsis thaliana
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DOI：
10.1021/pr0702159
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发表时间：
2007-09-01
影响因子：
4.4
通讯作者：
Gruissem, Wilhelm
中科院分区：
文献类型：
--
作者：
Bergmueller, Eveline;Gehrig, Peter M.;Gruissem, Wilhelm
真核DNA由碱性组蛋白H_2A、H_2B、H_3和H_4在结构上包装成染色质。越来越多的证据表明，组蛋白变体的掺入和翻译后修饰在基因调控中具有基础作用。虽然H3和H4的修饰历史现在已经确定，但对H2B的修饰知之甚少。在这里，我们首次详细描述了从模式植物拟南芥中分离出的H_2B变异体的特征。我们结合反相色谱和串联质谱仪来鉴定从总染色质和常染色质富集组分中分离出来的H2 B变异体HTB1、HTB2、HTB4、HTB9和HTB1的翻译后修饰。HTB9-变异体在赖氨酸6、11、27、32、38和39上有乙酰化位点，而Lys-145可以泛素化。HTB11发现了类似的修饰和Lys-3的额外甲基化。HtB2显示相似的乙酰化和泛素化位点，以及在Lys-11处的额外甲基化。此外，HTB9和HTB11的N-末端丙氨酸残基被发现是单甲基化、双甲基化或三甲基化或未修饰的。未检测到精氨酸残基甲基化。数据表明，这些修饰部位中的大多数只有部分被占用。我们的研究极大地扩展了共价拟南芥组蛋白修饰的图谱，是解开高等植物组蛋白密码的第一步。
Eukaryotic DNA is structurally packed into chromatin by the basic histone proteins H2A, H2B, H3, and H4. There is increasing evidence that incorporation and post-translational modifications of histone variants have a fundamental role in gene regulation. While modifications of H3 and H4 histories are now well-established, considerably less is known about H2B modifications. Here, we present the first detailed characterization of H2B-variants isolated from the model plant Arabidopsis thaliana. We combined reversed-phase chromatography with tandem mass spectrometry to identify post-translational modifications of the H2B-variants HTB1, HTB2, HTB4, HTB9, and HTB1 1, isolated from total chromatin and euchromatin-enriched fractions. The HTB9-variant has acetylation sites at lysines 6, 11, 27, 32, 38, and 39, while Lys-145 can be ubiquitinated. Analogous modifications and an additional methylation of Lys-3 were identified for HTB11. HTB2 shows similar acetylation and ubiquitination sites and an additional methylation at Lys-11. Furthermore, the N-terminal alanine residues of HTB9 and HTB11 were found to be mono-, di-, or trimethylated or unmodified. No methylation of arginine residues was detected. The data suggest that most of these modification sites are only partially occupied. Our study significantly expands the map of covalent Arabidopsis histone modifications and is the first step to unraveling the histone code in higher plants.