Department of Nephrology, Royal Melbourne Hospital, Parkville, Victoria, Australia.
Department of Medicine, Royal Melbourne Hospital, University of Melbourne, Parkville, Victoria, Australia.
Am J Physiol Renal Physiol. 2019 Sep 1;317(3):F606-F615. doi: 10.1152/ajprenal.00262.2019. Epub 2019 Jul 3.
Posttranslational modification of nucleosomal histones is a major determinant of chromatin structure and gene activity. In the present study, we hypothesized that unilateral ureteric obstruction (UUO), a widely used model of tubulointerstitial injury, would be associated with a distinct pattern of histone modifications (marks) in the kidney. Mass spectrometry was used to profile 63 different histone marks in normal mouse kidneys and those after 10 days of UUO. A subsequent histochemical analysis further examined examples of specific marks that changed significantly after UUO for which antisera are available. Histone marks were much more widely distributed and abundant in the normal kidney than is usually appreciated. Although aggregate analysis of the mass spectrometry results revealed net differences between control and UUO groups, residue-specific variations were subtle. Of the 16/63 significant changes ( < 0.05), only 8 changes were quantitatively different by >5%. Nevertheless, we identified several that are not usually examined in the kidney, including marks in the globular domain of core histones (H3:K79), linker histones (H1.4), and histone variants (H3.1:K27 and H3.3:K27). In several cases, there were complementary changes in different marks on the same amino acid. Using H3:K79ME2 as an example, mark enrichment was heterogeneous but largely colocalized with active transcription in a subset of tubular pathology. In conclusion, our study highlights the importance of unbiased screening in examining histone marks. Simultaneous changes in multiple marks on the same amino acid indicate a coordinated histone mark signature. The heterogeneous enrichment of marks, even within the same tubule, highlights the importance of regulatory context.
核小体组蛋白的翻译后修饰是染色质结构和基因活性的主要决定因素。在本研究中，我们假设单侧输尿管梗阻 (UUO)，一种广泛用于肾小管间质损伤的模型，与肾脏中独特的组蛋白修饰 (标记) 模式有关。质谱法用于分析正常小鼠肾脏和 UUO 后 10 天的肾脏中的 63 种不同组蛋白标记。随后的组织化学分析进一步检查了 UUO 后发生明显变化且有相应抗体的特定标记。与通常的理解相比，组蛋白标记在正常肾脏中的分布更为广泛和丰富。尽管对质谱结果的综合分析显示对照组和 UUO 组之间存在净差异，但残基特异性变化很细微。在 16/63 个显著变化 ( < 0.05) 中，只有 8 个变化的差异超过 5%。尽管如此，我们还是确定了一些在肾脏中通常不被检查的标记，包括核心组蛋白 (H3:K79)、连接组蛋白 (H1.4) 和组蛋白变体 (H3.1:K27 和 H3.3:K27) 球状结构域中的标记。在几种情况下，同一氨基酸上的不同标记会发生互补变化。以 H3:K79ME2 为例，标记富集不均匀，但在肾小管病变的一部分中主要与活跃的转录共定位。总之，我们的研究强调了在检查组蛋白标记时进行无偏筛选的重要性。同一氨基酸上多个标记的同时变化表明存在协调的组蛋白标记特征。即使在同一肾小管内，标记的不均匀富集也突出了调节背景的重要性。
