Structural basis of RNA conformational switching in the transcriptional regulator 7SK RNP

Yuan Yang; Shiheng Liu; Sylvain Egloff; Catherine D Eichhorn; Tanya Hadjian; James Zhen; Tamás Kiss; Z Hong Zhou; Juli Feigon

doi:10.1016/j.molcel.2022.03.001

Structural basis of RNA conformational switching in the transcriptional regulator 7SK RNP

Mol Cell. 2022 May 5;82(9):1724-1736.e7. doi: 10.1016/j.molcel.2022.03.001. Epub 2022 Mar 22.

Authors

Yuan Yang¹, Shiheng Liu², Sylvain Egloff³, Catherine D Eichhorn¹, Tanya Hadjian¹, James Zhen⁴, Tamás Kiss⁵, Z Hong Zhou⁶, Juli Feigon⁷

Affiliations

¹ Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA 90095, USA.
² Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA 90095, USA; California NanoSystems Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA.
³ Molecular, Cellular, and Developmental Biology Department (MCD), Centre de Biologie Intégrative (CBI), University of Toulouse, CNRS, UPS, 31062 Toulouse, France.
⁴ Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA 90095, USA; California NanoSystems Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA.
⁵ Molecular, Cellular, and Developmental Biology Department (MCD), Centre de Biologie Intégrative (CBI), University of Toulouse, CNRS, UPS, 31062 Toulouse, France; Biological Research Centre, Szeged, Temesvári krt. 62, 6726, Hungary.
⁶ Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA 90095, USA; California NanoSystems Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA. Electronic address: hong.zhou@ucla.edu.
⁷ Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA 90095, USA. Electronic address: feigon@mbi.ucla.edu.

Abstract

7SK non-coding RNA (7SK) negatively regulates RNA polymerase II (RNA Pol II) elongation by inhibiting positive transcription elongation factor b (P-TEFb), and its ribonucleoprotein complex (RNP) is hijacked by HIV-1 for viral transcription and replication. Methylphosphate capping enzyme (MePCE) and La-related protein 7 (Larp7) constitutively associate with 7SK to form a core RNP, while P-TEFb and other proteins dynamically assemble to form different complexes. Here, we present the cryo-EM structures of 7SK core RNP formed with two 7SK conformations, circular and linear, and uncover a common RNA-dependent MePCE-Larp7 complex. Together with NMR, biochemical, and cellular data, these structures reveal the mechanism of MePCE catalytic inactivation in the core RNP, unexpected interactions between Larp7 and RNA that facilitate a role as an RNP chaperone, and that MePCE-7SK-Larp7 core RNP serves as a scaffold for switching between different 7SK conformations essential for RNP assembly and regulation of P-TEFb sequestration and release.

Keywords: 7SK; La-related protein; Larp7; MePCE; RNP; cryo-electron microscopy; methylphosphate capping enzyme; non-coding RNA conformation; structure; transcription regulation.

Publication types

Research Support, N.I.H., Extramural
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

Molecular Conformation
Positive Transcriptional Elongation Factor B* / genetics
Positive Transcriptional Elongation Factor B* / metabolism
RNA* / genetics
RNA, Small Nuclear / genetics
Ribonucleoproteins / metabolism
Transcription, Genetic

Substances

RNA, Small Nuclear
Ribonucleoproteins
RNA
Positive Transcriptional Elongation Factor B

Abstract

Publication types

MeSH terms

Substances

Grants and funding