a, Intact capsids recruit CypA and CPSF6 which direct the virus to the nucleus. CPSF6 interaction prevents premature DNA synthesis. Excess cytoplasmic DNA is degraded by TREX1. At the nuclear pore CPSF6 NLS-dependent dissociation from the virus allows reverse transcription to proceed. Reverse-transcribed DNA crosses the nuclear membrane and integrates. b, c, Disruption of CypA–CA interactions with either CA(P90A) mutation or cyclosporine treatment leads to detection of DNA reverse transcription product by cGAS initiating cGAMP production, STING activation, NF-κB/IRF3 nuclear localization, type I interferon secretion and initiation of an antiviral state. d, e, Disruption of CPSF6-CA interactions by N74D CA mutation, or depletion of CPSF6, leads to activation of a cryptic innate DNA sensor which also activates NF-κB/IRF3 nuclear localization. f, Disruption of CPSF6 engagement with the nuclear transport machinery by mutating its NLS prevents reverse transcription because the CPSF6 does not dissociate from the capsid at the nuclear pore. (g) PF74 mimics CPSF6 by inserting a phenyl ring into a CA pocket in the same position as CPSF6 and also prevents reverse transcription. Like CPSF6ΔNLS PF74 has no NLS and thus does not disengage from the core and therefore terminally prevents reverse transcription.