Benzbromarone

Hit compounds were purchased from Namiki Syoji Co. Ltd (Tokyo, Japan) and dissolved in 100% dimethyl sulfoxide (DMSO). Benzbromarone was purchased from Tokyo Chemical Industry Co. Ltd (Tokyo, Japan) and dissolved in 100% DMSO. Oseltamivir phosphate purchased from F. Hoffmann-La Roche Ltd (Basel, Switzerland) was dissolved in phosphate-buffered saline (PBS) at a concentration of 10 mM. All of the compounds were maintained at −30 °C until use. Before performing the experiments, the compounds were diluted with Eagle’s minimum essential medium (MEM) supplemented with 1% 100× vitamin solution (MEM vitamin). HeLa cells were obtained from Dr Takujiro Homma (Nagasaki University, Japan) and maintained in Dulbecco’s modified Eagle’s medium (Sigma Aldrich, St Louis, MO) containing 10% fetal bovine serum (FBS). MDCK cells kindly donated by Dr Kyosuke Nagata (Tsukuba University, Japan) were grown in MEM supplemented with 5% FBS. These cells were maintained at 37 °C in an atmosphere of 5% CO₂. Influenza viruses were prepared as described previously^{48 (link)} and stored at −80 °C. Anti-HA (GTX127357), -M1 (GTX125928), -PA (GTX118991), -PB1 (GTX125923) and -NP (GTX125989) antibodies were purchased from GeneTex, Inc. (Irvine, CA). Anti-actin (A5060) antibody was purchased from Sigma Aldrich.

Probenecid, febuxostat, and benzbromarone were purchased from Tokyo Chemical Industry Co., Ltd. (Tokyo, Japan). Dotinurad was synthesized by Fuji Yakuhin Co., Ltd. (Saitama, Japan). IS potassium salt was purchased from Nacalai Tesque, Inc. (Kyoto, Japan). d⁴-IS potassium salt was purchased from Toronto Research Chemicals, Inc. (Toronto, Canada). Methyl cellulose 400 (MC) was purchased from Wako Pure Chemical Industries, Ltd. (Osaka, Japan). The TaqMan Fast Universal PCR Master Mix was purchased from Thermo Fisher Scientific, Inc. (Waltham, MA). SsoAdvanced Universal SYBR Green Supermix, Precision Plus Protein WesternC Standards, Precision StrepTactin HRP-conjugate, and Clarity Western ECL Substrate were purchased from Bio-Rad Laboratories, Inc. (Hercules, CA). Tris-SDS sample buffer was purchased from Kishida Chemical Co., Ltd. (Osaka, Japan). Primers and antibodies are described in Supplemental Table 4. The other drugs used in the present study are commercially available.