Cells were sorted as described in “Tissue Preparation and Flow Cytometry” and immediately lysed with RLT Buffer from the Qiagen RNeasy Plus Mini kit or RNA extraction buffer from PicoPure RNA isolation kit (Arcturus Bioscience, Inc.). Cell lysates were stored at −80°C until RNA was extracted. RNA isolations were performed using the Qiagen RNeasy Plus Mini kit or PicoPure RNA isolation kit. RNA quality and quantity were measured using the Agilent Technologies High Sensitivity RNA ScreenTape System. SMART-Seq v4 Ultra Low Input RNA kit (Clontech Laboratories, Inc.) was used for full-length cDNA synthesis, and the Nextera XT DNA sample preparation kit (Illumina Inc.) was used for library preparation. DNA libraries were sequenced on an Illumina NextSeq 500 instrument with a target read depth of ∼10 million aligned reads per sample. The pool was denatured and diluted, resulting in a 2.5 pM DNA solution. PhiX control was spiked at 1%, and the pool was sequenced by 1 × 75 cycles using the NextSeq 500 High Output reagent kit (Illumina Inc.).