Overview:
Acetylation of the histone tail causes chromatin to adopt an “open” conformation, allowing trans factors increased accessibility to DNA. The identification of histone acetyltransferases (HATs) and their large multiprotein complexes has yielded important insights into how these enzymes regulate transcription (1,2). HAT complexes interact with sequence-specific activator proteins to target specific genes. In addition to histones, HATs can acetylate non-histone proteins, suggesting multiple roles for these enzymes (3). In contrast, histone deacetylation promotes a “closed” chromatin conformation and typically leads to repression of gene activity (4). Mammalian histone deacetylases can be divided into three classes on the basis of their similarity to various yeast deacetylases (5). Class I (HDACs 1, 2, 3 and 8) proteins are related to the yeast Rpd3-like proteins, those in class II (HDACs 4, 5, 6, 7, 9 and 10) are related to yeast Hda1-like proteins and class III proteins are related to the yeast protein Sir2. Inhibitors of HDAC activity are now being explored as potential therapeutic cancer agents (6,7).
References:
1. Marmorstein, R. et al. (2001) Cell. Mol. Life Sci. 58, 693–703.2. Gregory, P.D. et al. (2001) Exp. Cell Res. 265, 195–202.3. Liu, Y. et al. (2000) Mol. Cell. Biol. 20, 5540–5543.4. Cress, S.D. and Seto, E. (2000) J. Cell. Physiol. 184, 1–16.5. Gray, S.G. and Ekstrom, T.J. (2001) Exp. Cell Res. 262, 75–83.6. Thiagalingam, S. et al. (2003) Ann. N. Y. Acad. Sci. 983, 84–100.7. Viguishin, D.M. and Coombes, R.C. (2004) Curr. Cancer Drug Targets 4, 205–218.
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这三样药是能混合在一起吃？
谢谢。
深夜，保姆觉得无聊就想去楼下看电视。但是她看不了，因为楼下没有电视（因为孩子的父母不希望他们的孩子看太多垃圾）。她就打电话给孩子的父母，问是否可以在他们的卧室看电视，当然孩子的父母同意了。
但保姆又想要最后一个请求。
她问是否可以用毯子或者衣服盖住那小丑雕像，因为那使她感到很害怕。
电话沉默了一会。
（此时爸爸在和保姆通话）
他说：带孩子离开房间……
我们将会叫警察……我们从来没有什么小丑雕像。
那小丑很可能是一个从监狱逃出来的杀人犯。
电话里沉默了一会儿。
（正在跟保姆通话的孩子的父亲）说：带上孩子们，离开房子……我们会通知警察……我们没有一个小丑雕像……
孩子们和保姆被小丑谋杀了。
结果是，小丑是一个从监狱里逃出来的杀人犯。
如果你不在5分钟内转发这个贴子，这个小丑在凌晨3点时将会拿着刀站在你的床前。
我在这里发了，这就是恶魔般的小丑没有杀我的原因
