A structure-based mechanism for displacement of the HEXIM adapter from 7SK small nuclear RNA.

ABSTRACT: Productive transcriptional elongation of many cellular and viral mRNAs requires transcriptional factors to extract pTEFb from the 7SK snRNP by modulating the association between HEXIM and 7SK snRNA. In HIV-1, Tat binds to 7SK by displacing HEXIM. However, without the structure of the 7SK-HEXIM complex, the constraints that must be overcome for displacement remain unknown. Furthermore, while structure details of the Tat^NL4-3-7SK complex have been elucidated, it is unclear how subtypes with more HEXIM-like Tat sequences accomplish displacement. Here we report the structures of HEXIM, Tat^G, and Tat^Fin arginine rich motifs in complex with the apical stemloop-1 of 7SK. While most interactions between 7SK with HEXIM and Tat are similar, critical differences exist

SUBMITTER: Pham VV 

PROVIDER: S-EPMC9378691 | biostudies-literature | 2022 Aug

REPOSITORIES: biostudies-literature