Identification of SERINC5-001 as the Predominant Spliced Isoform for HIV-1 Restriction

作者：Xianfeng Zhang, Tao Zhou, Jie Yang, Yu-Mei Lin, Jing Shi, Xi-He Zhang, Dylan Frabutt, Xiangwei Zeng, Sunan Li, Patrick J. Venta, Yong‐Hui Zheng · 发表于：Journal of Virology · 年份：2017 · DOI：10.1128/jvi.00137-17 · 被引用次数：50 · 研究领域：HIV Research and Treatment、HIV/AIDS drug development and treatment、HIV/AIDS Research and Interventions

ABSTRACT Among the five serine incorporator (SERINC) family members, SERINC5 (Ser5) was reported to strongly inhibit HIV-1 replication, which is counteracted by Nef. Ser5 produces 5 alternatively spliced isoforms: Ser5-001 has 10 putative transmembrane domains, whereas Ser5-004, -005, -008a, and -008b do not have the last one. Here, we confirmed the strong Ser5 anti-HIV-1 activity and investigated its isoforms' expression and antiviral activities. It was found that Ser5-001 transcripts were detected at least 10-fold more than the other isoforms by real-time quantitative PCR. When Ser5-001 and its two isoforms Ser5-005 and Ser5-008a were expressed from the same mammalian expression vector, only Ser5-001 was stably expressed, whereas the others were poorly expressed due to rapid degradation. In addition, unlike the other isoforms, which are located mainly in the cytoplasm, Ser5-001 is localized primarily to the plasma membrane. To map the critical determinant, Ser5 mutants bearing C-terminal deletions were created. It was found that the 10th transmembrane domain is required for Ser5 stable expression and plasma membrane localization. As expected, only Ser5-001 strongly inhibits HIV-1 infectivity, whereas the other Ser5 isoforms and mutants that do not have the 10th transmembrane domain show very poor activity. It was also observed that the Nef counteractive activity could be easily saturated by Ser5 overexpression. Thus, we conclude that Ser5-001 is the predominant antiviral is...