Tryptone phosphate broth

Pv11 cells were originally established in our laboratory [14 (link)]. Pv11 cells and all clonal cell lines were grown in IPL-41 medium (Thermo Fisher Scientific, Waltham, MA, USA) supplemented with 2.6 g/L tryptone phosphate broth (Becton, Dickinson and Company, Franklin Lakes, NJ), 10% (v/v) fetal bovine serum (MP Biomedicals, Santa Ana, CA, USA), and 0.05% (v/v) of an antibiotic and antimycotic mixture (penicillin, amphotericin B, and streptomycin; Merck KGaA, Darmstadt, Germany).

Pv11 cells were originally established in our laboratory [27 (link)]. The cell culture was maintained as described [15 (link)]. Briefly, Pv11 cells were cultured using IPL-41 medium (Thermo Fisher Scientific, Waltham, MA, USA) supplemented with 2.6 g/L tryptone phosphate broth (Becton, Dickinson and Company, Franklin Lakes, NJ, USA), 10% (v/v) fetal bovine serum (MP Biomedicals, Santa Ana, CA, USA) and 0.05% (v/v) of an antibiotic and antimycotic mixture (penicillin, amphotericin B, and streptomycin; Merck KGaA, Darmstadt, Germany). As trehalose treatment, the cells were incubated in trehalose mixture (600 mM trehalose (Hayashibara Co., Ltd., Okayama, Japan) containing 10% (v/v) IPL-41 medium).

BHK/T7-9 cells stably expressing T7 RNA polymerase (kindly provided by Dr. Makoto Sugiyama and Dr. Naoto Ito, Faculty of Applied Biological Science, Gifu University) were maintained in minimum essential medium (Gibco, Thermo Fisher Scientific, Life Technologies, Waltham, MA, USA) supplemented with heat-deactivated 5% fetal bovine serum (Biowest, Nuaille, France), 10% tryptone phosphate broth (Becton, Dickinson and Company, Sparks, MD, USA), and 1% penicillin/streptomycin (Sigma Aldrich CO., St. Louis, MO, USA). Cells were selected by hygromycin B (Invitrogen, Thermo Fisher Scientific, Life Technologies, Waltham, MA, USA) every 10 passages. HEK293T cells were maintained in Dulbecco’s modified Eagle’s medium—high glucose (Sigma Aldrich CO.) supplemented with heat-deactivated 10% fetal bovine serum and 1% penicillin/streptomycin.