To investigate gene expression, SV40 immortalized MEFs were plated in triplicates in 60 mm dishes (430166, Corning) in 4 ml standard growth media. After 24 hours, MEFs were washed once with 4 ml D-PBS (14190169, Thermo Fisher Scientific) and RNA was isolated using the TRI reagent (T9424, Sigma-Aldrich, Thermo Fisher Scientific) according to the manufacturer's protocols. RNA concentrations were determined with a NanoDrop 8000 (Thermo Fisher Scientific). RNA quality was assessed on a Fragment Analyzer (Agilent Technologies) and all RNAs had a RQN above 9.3. RNA-seq libraries were prepared from 500 ng of total RNA with the Illumina TruSeq Stranded mRNA reagents (Illumina) using a unique dual indexing strategy, and following the official protocol. Libraries were quantified by a fluorimetric method (QubIT, Life Technologies) and their quality assessed on a Fragment Analyzer (Agilent Technologies). Sequencing was performed on an Illumina NovaSeq 6000 for 100 cycles single read.