Structural basis for the recognition of RNA polymerase II C-terminal domain by CREPT and pl5RS

• Published in: 中国科学：生命科学英文版 2014 (1), p.97-106
• Main Author: MEI KunRong JIN Zhe REN FangLi WANG YinYing CHANG ZhiJie WANG XinQuan
• Format: Article
• Language: English
• Subjects: C-末端; RNA聚合酶; 同源蛋白; 序列同源性; 晶体结构; 结构域; 结构基础; 识别
• ISSN: 1674-7305; 1869-1889

CREPT and p15RS are two recently identified homologous proteins that regulate cell proliferation in an opposite way and are closely related to human cancer development. Both CREPT and pl5RS consist of an N-terminal RPR domain and a C-terminal domain with high sequence homology. The transcription enhancement by CREPT is attributed to its interaction with RNA polymerase II （Pol II）. Here we provide biochemical and structural evidence to support and extend this molecular mechanism. Through fluorescence polarization analysis, we show that the RPR domains of CREPT and pl5RS （CREPT-RPR and pI5RS-RPR） bind to different Pol II C-terminal domain （CTD） phosphoisoforms with similar affinity and specificity. We also determined the crystal structure of pl5RS-RPR. Sequence and structural comparisons with RPR domain of Rttl03, a homolog of CREPT and p l5RS in yeast, reveal structural basis for the similar binding profile of CREPT-RPR and p 15RS-RPR with Pol II CTD. We also determined the crystal structure of the C-terminal domain of CREPT （CREPT-CTD）, which is a long rod-like dimer and each monomer adopts a coiled-coil structure. We propose that dimerization through the C-terminal domain enhances the binding strength between CREPT or pl5RS with Pol II by increasing binding avidity. Our results collectively reveal the respective roles of N-terminal RPR domain and C-terminal domain of CREPT and pl5RS in recognizing RNA Pol II.