title: polyA RNA sequencing of STL001 Left Ventricle Cultured Cells
design: Four µg of total RNA was extracted from frozen cell pellets using the RNeasy Mini Kit (Qiagen, Valencia, CA). PolyA RNA was isolated from total RNA using Dynabeads oligo(dt)25 (Invitrogen). PolyA selected RNA was eluted in 2x Superscript III buffer supplemented with 10mM DTT and was fragmented by incubation at 94°C for 4 minutes. First-strand cDNA was synthesized with the following reaction composition: 0.5 µL random hexamer, 0.5 µL RNase Out, 1 µL DTT (100 mM), 0.5 µL dNTP (25 mM), 0.5 µL SuperScript III (20 µL final). The reaction was incubated at 25°C for 10 min then 50°C for 50 min.  Single-stranded cDNA was isolated by purification with RNAClean XP beads (Beckman Coulter Genomics, Danvers, MA). The dUTP-containing second-strand was synthesized with the following reaction: 1.5 µL NEBuffer 2 (NEB), 1 µL dNTP mix (10 mM dATP, dCTP, dGTP, and dUTP), 0.2 µL RNase H, 1 µL DNA Polymerase I (E. coli) (New England Biolabs) (15 µL final). The reaction was incubated at 16°C for 2.5 hours. The dUTP-containing cDNA was isolated by purification with AMPure XP beads (Beckman Coulter Genomics, Danvers, MA). The dUTP-containing cDNA was then end repaired and a 3'A base was added. TruSeq adapters (Illumina, San Diego, CA) were ligated to the dUTP-containing cDNA at 16°C for 16 hours with T4 DNA ligase (New England Biolabs). Adapter-ligated cDNA was isolated by two rounds of purification with AMPure XP beads. The dUTP-containing strands were digested at 37°C for 30 min with uracil DNA glycosylase (Enzymatics). Adapter-ligated, single-stranded DNA molecules were enriched by 10 cycles of PCR with the following reaction composition: 5 µL TruSeq PCR Primer Cocktail (Illumina), 25 µL TruSeq PCR Master Mix (Illumina) (50 µL final). The thermocycling parameters were: 98°C 30 sec, then 10-15 cycles of 98°C 10 sec, 60°C 30 sec and 72°C 30 sec, ending with one 72°C 5 min step. The reaction products were purified using AMPure XP beads. 