293t crl 3216 cells

293T CRL-3216 cells were purchased from ATCC and authenticated by the supplier. All cells are regularly tested and are mycoplasma free. Gag/Pol and GFP vectors were, respectively, for HIV-1 pCRV-1(Zennou et al., 2004 (link)) and CSGW(Naldini et al., 1996 (link)); for HIV-2, HIV-2 ROD Gag/Pol and HIV-2 GFP(Griffin et al., 2001 (link)); for HIV-1 O p8.91 MVP(Ikeda et al., 2004 (link)); for SIVmac, SIV3⁺ and SIV-eGFP(Poeschla et al., 1998 (link)) and for FIV FP93(Poeschla et al., 1998 (link)). Lentiviral packaging plasmid pMDG2, which encodes VSV-G envelope, was used to pseudotype infectious virions (Addgene plasmid # 12259). Cells for depletion of TNPO3 and NUP358 were produced by expression of shRNAs as previously described(Schaller et al., 2011 (link)). HEK293T and HeLa cell lines were maintained in Dulbecco’s modified Eagle’s medium (DMEM) with 10% FBS, 2 mM L-glutamine, 100 U/ml penicillin, and 100 μg/ml streptomycin (GIBCO) at 37°C with 5% CO₂. PBMCs were stimulated with 2 μg/ml PHA-P for 4 days before infection, then cultured in RPMI 1640 with 10% FBS, 2mM L-glutamine, 100 U/ml penicillin, 100 μg/ml streptomycin, and 50 U/ml IL-2.

WT and TRIM21-/- (K21) MEF cell lines were maintained in Dulbecco’s Modified Eagle Medium (DMEM) supplemented with 10% fetal calf serum, penicillin at 100 U/ml and streptomycin at 100 μg/ml. MEF cells were obtained from WT or TRIM21 knockout C57/B6 mice and have previously been described and authenticated (Guilliams et al., 2014 (link)). Human adenovirus type five vector (ΔE1,ΔE3) expressing GFP (AdV) was purchased from ViraQuest. Human rhinovirus type 14 (HRV) was produced by infection of HeLa cells, and virus was purified by 2 rounds of CsCl centrifugation. 293T CRL-3216 cells were purchased from ATCC and authenticated by the supplier. All cells used are regularly tested and are mycoplasma free.

Human hypopharyngeal carcinoma FaDu cells (American Type Culture Collection, Manassas, VA, USA) and FaDu-3R cells harboring multiple reporter genes were maintained in RPMI-1640 (Life Technologies Inc., Carlsbad, CA, USA) with supplement of 10% fetal bovine serum (Thermo Fisher Scientific Inc., Waltham, MA, USA). The 293T cells (CRL-3216, American Type Culture Collection, Manassas, VA, USA) were cultured in Dulbecco's modified eagle medium (DMEM, Life Technologies Inc., Carlsbad, CA, USA) with 10% fetal bovine serum supplied. Cells were incubated at 37°C in a humidified incubator (Thermo Fisher Scientific Inc., Waltham, MA, USA) containing 5% CO₂.

WSN was propagated in MDCK cells. TJ186 and HB08 viruses were propagated in 10-day-old specific-pathogen-free (SPF) embryonated chicken eggs purchased from Beijing Vital River Animal Technology Co., Ltd. (Beijing, China) (licensed by Charles River) at 37 °C for 72 h. Human lung adenocarcinoma epithelial cells (A549 cells, CCL-185), Madin–Darby canine kidney cells (MDCK cells, CCL-34), and human embryonic kidney HEK293T cells (293T cells, CRL-3216) were purchased from the American Type Culture Collection (ATCC). The cells were cultured in Dulbecco’s modified Eagle’s medium (DMEM, Gibco, Grand Island, NY, USA), high glucose supplemented with 10% (v/v) fetal bovine serum (FBS, Gibco, Grand Island, NY, USA), 100 U/mL penicillin, and 100 μg/mL streptomycin (Sigma, St. Louis, MO, USA) at 37 °C in a humidified 5% CO₂ incubator.
The circRNA-shRNA plasmids were constructed using pSIH-shRNA. Briefly, the shRNA sequence was cloned into the BamHI/EcoRI sites of pSIH-shRNA. The shRNA sequences are listed in Supplementary Table S1. The circRNA sequences were cloned in the lentiviral pLC5-CIR vector (Gene-seed, Guangzhou, China) to construct overexpression plasmids. The homologous recombination amplification primers are listed in Supplementary Table S1.