Gelbart Marnie E, Larschan Erica, Peng Shouyong, Park Peter J, Kuroda Mitzi I
Division of Genetics, Department of Medicine, Brigham & Women's Hospital, Boston, Massachusetts, USA.
Nat Struct Mol Biol. 2009 Aug;16(8):825-32. doi: 10.1038/nsmb.1644. Epub 2009 Aug 2.
The Drosophila melanogaster male-specific lethal (MSL) complex binds the single male X chromosome to upregulate gene expression to equal that from the two female X chromosomes. However, it has been puzzling that approximately 25% of transcribed genes on the X chromosome do not stably recruit MSL complex. Here we find that almost all active genes on the X chromosome are associated with robust H4 Lys16 acetylation (H4K16ac), the histone modification catalyzed by the MSL complex. The distribution of H4K16ac is much broader than that of the MSL complex, and our results favor the idea that chromosome-wide H4K16ac reflects transient association of the MSL complex, occurring through spreading or chromosomal looping. Our results parallel those of localized Polycomb repressive complex and its more broadly distributed chromatin mark, trimethylated histone H3 Lys27 (H3K27me3), suggesting a common principle for the establishment of active and silenced chromatin domains.
果蝇雄性特异性致死（MSL）复合物结合单条雄性X染色体，上调基因表达，使其与两条雌性X染色体的基因表达水平相等。然而，令人困惑的是，X染色体上约25%的转录基因不能稳定招募MSL复合物。我们发现，X染色体上几乎所有活跃基因都与由MSL复合物催化的组蛋白修饰——组蛋白H4赖氨酸16乙酰化（H4K16ac）相关。H4K16ac的分布比MSL复合物的分布广泛得多，我们的结果支持这样一种观点，即全染色体范围的H4K16ac反映了MSL复合物的瞬时结合，这种结合通过扩散或染色体环化发生。我们的结果与局部的多梳抑制复合物及其分布更广泛的染色质标记——组蛋白H3赖氨酸27三甲基化（H3K27me3）的结果相似，这表明活跃和沉默染色质结构域的建立存在共同原则。
