Structural and functional insight into the effect of AFF4 dimerization on activation of HIV-1 proviral transcription

Dan Tang; Chunjing Chen; Ga Liao; Jiaming Liu; Banghua Liao; QingQing Huang; Qianqian Chen; Jiahui Zhao; Hui Jiang; Jinsong Duan; Jin Huang; Kunjie Wang; Jiawei Wang; Cuiyan Zhou; Wendan Chu; Wenqi Li; Bo Sun; Zhonghan Li; Lunzhi Dai; Xianghui Fu; Wei Cheng; Yuhua Xue; Shiqian Qi

doi:10.1038/s41421-020-0142-6

Structural and functional insight into the effect of AFF4 dimerization on activation of HIV-1 proviral transcription

Cell Discov. 2020 Feb 18:6:7. doi: 10.1038/s41421-020-0142-6. eCollection 2020.

Authors

Dan Tang^#¹, Chunjing Chen^#², Ga Liao³, Jiaming Liu¹, Banghua Liao¹, QingQing Huang², Qianqian Chen¹, Jiahui Zhao¹, Hui Jiang¹, Jinsong Duan⁴, Jin Huang¹, Kunjie Wang¹, Jiawei Wang⁴, Cuiyan Zhou⁵, Wendan Chu⁵, Wenqi Li⁵, Bo Sun⁶, Zhonghan Li¹, Lunzhi Dai¹, Xianghui Fu¹, Wei Cheng¹, Yuhua Xue², Shiqian Qi¹

Affiliations

¹ 1Department of Urology, State Key Laboratory of Biotherapy, West China Hospital, College of Life Sciences, Sichuan University, and Collaborative Innovation Center for Biotherapy, Chengdu, Sichuan 610041 China.
² 2School of Pharmaceutical Sciences, Xiamen University, Xiamen, Fujian 361102 China.
³ 3State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, Chinese Academy of Medical Sciences Research Unit of Oral Carcinogenesis and Management, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan 610041 China.
⁴ 4State Key Laboratory of Membrane Biology, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing, 100084 China.
⁵ School of Biomedicine in Tsinghua University, National Protein Science Facility, Beijing, 100084 China.
⁶ 6Shanghai Synchrotron Radiation Facility, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai, 201204 China.

^# Contributed equally.

Abstract

Super elongation complex (SEC) is a positive regulator of RNA polymerase II, which is required for HIV-1 proviral transcription. AFF1/4 is the scaffold protein that recruits other components of SEC and forms dimer depending on its THD domain (TPRL with Handle Region Dimerization Domain). Here we report the crystal structure of the human AFF4-THD at the resolution of 2.4 Å. The α4, α5, and α6 of one AFF4-THD mediate the formation of a dimer and pack tightly against the equivalent part of the second molecule in the dimer of AFF-THD. Mutagenesis analysis revealed that single mutations of either Phe1014 or Tyr1096 of AFF4 to alanine impair the formation of the AFF4 dimer. In addition, transactivation assay also indicated that Phe1014 and Tyr1096 of AFF4 are critical to the transactivation activity of AFF4. Interestingly, the corresponding residues Phe1063 and Tyr1145 in AFF1 have an effect on the transactivation of HIV-1 provirus. However, such mutations of AFF1/4 have no effect on the interaction of AFF1/4 with other subunits of the SEC. Together, our data demonstrated that the dimerization of AFF1/4 is essential to transactivation of HIV-1 provirus.

Keywords: Transcription; X-ray crystallography.