Ubiquityl-Histone H2B (Lys120) (D11) XP? Rabbit mAb

• 产品编号：CST-5546P      品牌：Cell Signaling Technology       原厂货号：5546P
• 产品分类：抗体 > 一抗 > 蛋白特异性一抗
• 应用分类：

描述：

Ubiquityl-Histone H2B (Lys120) (D11) XP® Rabbit mAb兔单抗能够检测仅在Lys120位点泛素化的内源性histone H2B蛋白水平。该抗体不能与其它泛素化蛋白或游离的泛素分子发生交叉反应。通过合成的仅在Lys120位点单泛素化的人源histone H2B蛋白羧基端周围相应的多肽片段去免疫动物从而制备出此单克隆抗体。核小体是由四种中心组蛋白(H2A、H2B、H3和H4)组成，它是染色质的主要构件模块。起初被认为是一个DNA包装的静态支架，目前组蛋白已经被认为是一个动态蛋白，其经历多种形式的翻译后修饰，包括乙酰化作用、磷酸化作用、甲基化作用和泛素化作用(1)。泛素是一个保守的76个氨基酸多肽单位，它通过泛素化过程共价连接许多细胞内蛋白。三个成分涉及蛋白质泛素化连接过程。泛素首先通过形成一个与活化元件E1一起的硫酯复合物被激活；随后活化的泛素转移到泛素载体蛋白E2，然后从E2传递到泛素连接酶E3的靶蛋白赖氨酸残基epsilon-NH2上(2)。在转录激活期间，通过RAD6 E2蛋白连接BRE1A/BRE1B E3 ligase (also known as RNF20/RNF40)从而使Histone H2B在Lys120位点发生单泛素化(3)。在PAF复合物激活期间，RAD6/BRE1复合物被招募到基因启动子，而PAF复合物是一个RNA polymerase II相关的蛋白复合物，它调节转录延伸(3-5)。Lys120位点单泛素化的histone H2B是与活化基因的转录区域有关联(3,6)。histone H2B的单泛素化通过促进FACT依赖的染色质重构从而刺激转录延伸(7,8)。此外，对于随后的histone H3在Lys4 和Lys79位点的甲基化有本质作用，这两个附加的组蛋白修饰能调节转录起始和延伸(9)。有趣的是，通过USP22使histone H2B蛋白lysine 120位点去泛素化在转录激活阶段是需要的，而USP22是人源SAGA组蛋白乙酰转移酶复合物中的一个亚单位(10)。因此，histone H2B的泛素水平在转录期间是动态的，并且可能作为转录激活中一个中间过程。

1. Peterson, C.L. and Laniel, M.A. (2004) Curr Biol 14, R546-51.
2. Liu, F. and Walters, K.J. (2010) Trends Biochem Sci 35, 352-60.
3. Kim, J. et al. (2009) Cell 137, 459-71.
4. Wood, A. et al. (2003) J Biol Chem 278, 34739-42.
5. Xiao, T. et al. (2005) Mol Cell Biol 25, 637-51.
6. Minsky, N. et al. (2008) Nat Cell Biol 10, 483-8.
7. Pavri, R. et al. (2006) Cell 125, 703-17.
8. Fleming, A.B. et al. (2008) Mol Cell 31, 57-66.
9. Shilatifard, A. (2006) Annu Rev Biochem 75, 243-69.
10. Wyce, A. et al. (2004) Novartis Found Symp 259, 63-73; discussion 73-7, 163-9.

原厂资料：

Specificity / Sensitivity

Ubiquityl-Histone H2B (Lys120) (D11) XP® Rabbit mAb detects endogenous levels of histone H2B protein only when ubiquitylated on Lys120. The antibody does not cross-react with other ubiquitylated proteins or free ubiquitin.

Source / Purification

Monoclonal antibody is produced by immunizing animals with a synthetic peptide corresponding to the carboxy terminus of the human histone H2B protein in which Lys120 is mono-ubiquitylated.

Background

The nucleosome, made up of four core histone proteins (H2A, H2B, H3 and H4), is the primary building block of chromatin. Originally thought to function as a static scaffold for DNA packaging, histones have now been shown to be dynamic proteins, undergoing multiple types of post-translational modifications, including acetylation, phosphorylation, methylation, and ubiquitylation (1). Ubiquitin is a conserved 76 amino acid peptide unit that can be covalently linked to many cellular proteins by the ubiquitylation process. Three components are involved in this protein-ubiquitin conjugation process. Ubiquitin is first activated by forming a thiolester complex with the activation component E1; the activated ubiquitin is subsequently transferred to the ubiquitin-carrier protein E2, then from E2 to ubiquitin ligase E3 for final delivery to the epsilon-NH2 of the target protein lysine residue (2). Histone H2B is mono-ubiquitylated on lysine 120 during transcriptional activation by the RAD6 E2 protein in conjunction with the BRE1A/BRE1B E3 ligase (also known as RNF20/RNF40) (3). The RAD6/BRE1 complex is recruited to gene promoters during activation by the PAF complex, an RNA polymerase II-associated protein complex that regulates transcriptional elongation (3-5). Mono-ubiquitylated histone H2B lysine 120 is associated with the transcribed region of active genes (3,6). Mono-ubiquitylation of histone H2B stimulates transcriptional elongation by facilitating FACT-dependent chromatin remodeling (7,8). In addition, it is essential for subsequent methylation of histone H3 lysines 4 and 79, two additional histone modifications that regulate transcriptional initiation and elongation (9). Interestingly, de-ubiquitylation of histone H2B lysine 120 by USP22, a subunit of the human SAGA histone acetyltransferase complex, is a required step in transcriptional activation (10). Thus, it appears that the ubiquitylation state of histone H2B is dynamic during transcription and may serve as an intermediate step in transcriptional activation.

1. Peterson, C.L. and Laniel, M.A. (2004) Curr Biol 14, R546-51.
2. Liu, F. and Walters, K.J. (2010) Trends Biochem Sci 35, 352-60.
3. Kim, J. et al. (2009) Cell 137, 459-71.
4. Wood, A. et al. (2003) J Biol Chem 278, 34739-42.
5. Xiao, T. et al. (2005) Mol Cell Biol 25, 637-51.
6. Minsky, N. et al. (2008) Nat Cell Biol 10, 483-8.
7. Pavri, R. et al. (2006) Cell 125, 703-17.
8. Fleming, A.B. et al. (2008) Mol Cell 31, 57-66.
9. Shilatifard, A. (2006) Annu Rev Biochem 75, 243-69.
10. Wyce, A. et al. (2004) Novartis Found Symp 259, 63-73; discussion 73-7, 163-9.

注意事项：

Storage: Supplied in 10 mM sodium HEPES (pH 7.5), 150
mM NaCl, 100 µg/ml BSA, 50% glycerol and less than 0.02%
sodium azide. Store at –20°C. Do not aliquot the antibody.