library_construction_protocol: For each sample, mRNA was isolated using RNeasy Plus Mini kits following the manufacturer's instructions (Qiagen) from between 1 x 106 and 1 x 107 cells.  Extracted total RNA quality and concentration were assessed on Fragment Analyzer (Agilent Technologies) and Qubit 2.0 (Thermo Fisher Scientific), respectively.  All samples had an RQN > 7. RNA-seq libraries were prepared using the commercially available KAPA Stranded mRNA-Seq Kit (Roche) using 500 ng of total RNA for each sample.  Illumina sequencing adapters were ligated to the output cDNA fragments and amplified to produce the final RNA-seq library with a dual-indexing approach for pooled library multiplex sequencing.