Aso T, Yamazaki K, Amimoto K, Kuroiwa A, Higashi H, Matsuda Y, Kitajima S, Hatakeyama M
Department of Viral Oncology, Cancer Institute, Japanese Foundation for Cancer Research, Tokyo 170-8455, Japan.
J Biol Chem. 2000 Mar 3;275(9):6546-52. doi: 10.1074/jbc.275.9.6546.
The Elongin complex stimulates the rate of transcription elongation by RNA polymerase II by suppressing the transient pausing of the polymerase at many sites along the DNA template. Elongin is composed of a transcriptionally active A subunit and two small regulatory B and C subunits, the latter of which bind stably to each other to form a binary complex that interacts with Elongin A and strongly induces its transcriptional activity. To further understand the roles of Elongin in transcriptional regulation, we attempted to identify Elongin-related proteins. Here, we report on the cloning, expression, and characterization of human Elongin A2, a novel transcription elongation factor that exhibited 47% identity and 61% similarity to Elongin A. Biochemical studies have shown that Elongin A2 stimulates the rate of transcription elongation by RNA polymerase II and is capable of forming a stable complex with Elongin BC. However, in contrast to Elongin A, its transcriptional activity is not activated by Elongin BC. Northern blot analysis revealed that Elongin A2 mRNA was specifically expressed in the testis, suggesting that Elongin A2 may regulate the transcription of testis-specific genes.
Elongin复合物通过抑制RNA聚合酶II在DNA模板上多个位点的短暂停顿来刺激转录延伸速率。Elongin由一个具有转录活性的A亚基以及两个小的调节性B和C亚基组成，后两者彼此稳定结合形成一个二元复合物，该复合物与Elongin A相互作用并强烈诱导其转录活性。为了进一步了解Elongin在转录调控中的作用，我们试图鉴定与Elongin相关的蛋白质。在此，我们报告了人类Elongin A2的克隆、表达及特性分析，Elongin A2是一种新型转录延伸因子，与Elongin A具有47%的同一性和61%的相似性。生化研究表明，Elongin A2刺激RNA聚合酶II的转录延伸速率，并且能够与Elongin BC形成稳定复合物。然而，与Elongin A不同，其转录活性不会被Elongin BC激活。Northern印迹分析显示，Elongin A2 mRNA在睾丸中特异性表达，提示Elongin A2可能调控睾丸特异性基因的转录。
