[1] Samuel Lunenfeld Research Institute, Mount Sinai Hospital, Toronto, Ontario, Canada. [2] These authors contributed equally to this work.
Nat Struct Mol Biol. 2010 Mar;17(3):299-305. doi: 10.1038/nsmb.1754. Epub 2010 Feb 7.
Phosphorylation of histone H2AX is an early response to DNA damage in eukaryotes. In Saccharomyces cerevisiae, DNA damage or replication-fork stalling results in phosphorylation of histone H2A yielding gamma-H2A (yeast gamma-H2AX) in a Mec1 (ATR)- and Tel1 (ATM)-dependent manner. Here, we describe the genome-wide location analysis of gamma-H2A as a strategy to identify loci prone to engaging the Mec1 and Tel1 pathways. Notably, gamma-H2A enrichment overlaps with loci prone to replication-fork stalling and is caused by the action of Mec1 and Tel1, indicating that these loci are prone to breakage. Moreover, about half the sites enriched for gamma-H2A map to repressed protein-coding genes, and histone deacetylases are necessary for formation of gamma-H2A at these loci. Finally, our work indicates that high-resolution mapping of gamma-H2AX is a fruitful route to map fragile sites in eukaryotic genomes.
组蛋白 H2AX 的磷酸化是真核生物对 DNA 损伤的早期反应。在酿酒酵母中，DNA 损伤或复制叉停滞导致组蛋白 H2A 的磷酸化，产生 γ-H2A（酵母 γ-H2AX），这一过程依赖于 Mec1（ATR）和 Tel1（ATM）。在这里，我们描述了全基因组范围内 γ-H2A 的定位分析，作为鉴定易发生 Mec1 和 Tel1 途径的基因座的策略。值得注意的是，γ-H2A 的富集与易发生复制叉停滞的基因座重叠，并且是由 Mec1 和 Tel1 的作用引起的，表明这些基因座容易发生断裂。此外，大约一半富含 γ-H2A 的位点映射到被抑制的蛋白质编码基因上，并且组蛋白去乙酰化酶对于这些基因座处 γ-H2A 的形成是必需的。最后，我们的工作表明，γ-H2AX 的高分辨率作图是在真核基因组中绘制脆性位点的有效途径。
