Reiterative Enrichment and Authentication of CRISPRi Targets (REACT) identifies the proteasome as a key contributor to HIV-1 latency

PLoS Pathog. 2019 Jan 15;15(1):e1007498. doi: 10.1371/journal.ppat.1007498. eCollection 2019 Jan.


The establishment of HIV-1 latency gives rise to persistent chronic infection that requires life-long treatment. To reverse latency for viral eradiation, the HIV-1 Tat protein and its associated ELL2-containing Super Elongation Complexes (ELL2-SECs) are essential to activate HIV-1 transcription. Despite efforts to identify effective latency-reversing agents (LRA), avenues for exposing latent HIV-1 remain inadequate, prompting the need to identify novel LRA targets. Here, by conducting a CRISPR interference-based screen to reiteratively enrich loss-of-function genotypes that increase HIV-1 transcription in latently infected CD4+ T cells, we have discovered a key role of the proteasome in maintaining viral latency. Downregulating or inhibiting the proteasome promotes Tat-transactivation in cell line models. Furthermore, the FDA-approved proteasome inhibitors bortezomib and carfilzomib strongly synergize with existing LRAs to reactivate HIV-1 in CD4+ T cells from antiretroviral therapy-suppressed individuals without inducing cell activation or proliferation. Mechanistically, downregulating/inhibiting the proteasome elevates the levels of ELL2 and ELL2-SECs to enable Tat-transactivation, indicating the proteasome-ELL2 axis as a key regulator of HIV-1 latency and promising target for therapeutic intervention.

Publication types

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

MeSH terms

  • Anti-HIV Agents / therapeutic use
  • CD4-Positive T-Lymphocytes / metabolism
  • CRISPR-Cas Systems
  • Cell Line
  • Clustered Regularly Interspaced Short Palindromic Repeats
  • Gene Editing / methods
  • HIV Infections / drug therapy
  • HIV Infections / metabolism
  • HIV Seropositivity
  • HIV-1 / metabolism*
  • HIV-1 / pathogenicity
  • Humans
  • Jurkat Cells
  • Proteasome Endopeptidase Complex / metabolism*
  • Proteasome Endopeptidase Complex / physiology
  • Proteasome Inhibitors / metabolism
  • Proteasome Inhibitors / pharmacology
  • Transcriptional Elongation Factors
  • Virus Activation / drug effects
  • Virus Latency / drug effects*
  • Virus Latency / physiology


  • Anti-HIV Agents
  • Proteasome Inhibitors
  • Transcriptional Elongation Factors
  • Proteasome Endopeptidase Complex