Cells were sorted at 4C by flow cytometry into tubes containing RPMI.  Following centrifugation, cells were homogenized in 350uL Buffer RLT containing 1% 2-Mercaptoethanol and extracted using the RNeasy Micro kit (Qiagen) with on-column DNase digestion. RNA quality was assessed using a Fragment Analyzer (Agilent), and then 0.5 nanograms of total RNA was used as input for cDNA synthesis using the Clontech SMART-Seq v4 Ultra Low Input RNA kit (Takara Bio) according to the manufacturer's instructions.  Amplified cDNA was fragmented and appended with dual-indexed bar codes using the Nextera XT DNA Library Preparation Kit (Illumina).  Libraries were validated by capillary electrophoresis on a Fragment Analyzer (Agilent), pooled at equimolar concentrations, and sequenced on an Illumina NovaSeq6000 at 100SR, yielding 20 million reads per sample.