library_construction_protocol: Cells were isolated by FACS, and collected into trizol. RNA was extracted using the Direct-zol RNA extraction kit (Zymo) following manufacturer's instructions. RNA quality was determined by Agilent 2100 Bioanalyzer, and cDNA libraries were prepared using the Illumina TrueSeq mRNA sample preparation kit. Libraries were sequenced on an Illumina HiSeq 4000 or NovaSeq instrument as indicated.