STEMCCA lentivirus, which express all reprogramming factors from a polycistronic transcript [18 (link)], was prepared as described [19 (link)]. Primary LGG cells were transduced with the STEMCCA lentivirus at an MOI of 3 as described [20 (link)]. Three days after transduction, the LGG cells were reseeded onto cell culture plates-coated with hESC-qualified Geltrex basement membrane matrix (Thermo Fisher) at a density of 1−3×105 cells/cm2 in LGG medium. The cells were then cultured in E7 medium (E8 medium without TGF-β) from the following day for two weeks and in E8 medium for one to two weeks as described [20 (link)–22 (link)]. Independent clones of iPSCs were manually picked into Geltrex-coated 12-well tissue culture plates and maintained in E8 medium as described [23 (link),24 (link)].