High-troughput expression profile of long non-coding and protein-coding RNAs in primary murine aortic endothelial cells (MAoECs)

strand specific sequencing of RNAs from MAoECs to determine the endothelial-specific expression profile of protein-coding and long non-coding RNAs Total RNA was isolated from cultured MAoECs (passage 4) and processed for a strand-specific RNA sequencing. The RNA purity and integrity were assessed using the Fragment Analyzer Automated CE System (Advanced Analytical). A RQN of 8.8 and a 28S/18S ratio of 2.2 were considered acceptable for next generation sequencing assay. Five µg of DNase-treated RNA were used to prepare Massive Analysis of cDNA ends (MACE) libraries needed to perform a DNA-Methylation-Sequencing (Meth-Seq) PCR bias free quantification with TrueQuant Technology, followed by a high-throughput sequencing on the Illumina Genome Analyzer II system (GenXPro GmbH, Frankfurt, Germany). The procedure consist in the extraction of poly-adenylated RNA from 5 µg RNA and reverse transcribed with biotinylated poly(T) primers. cDNA is fragmented to an average size of 250 bp. Biotinylated ends are captured by streptavidin beads and ligated to modified adapters (TrueQuant DNA adapter, GenXPro). The libraries are amplified by PCR, purified by SPRI beads and sequenced (2 x 100 bp Illumina HiSeq2000 TrueSeq, 2 x 20 Mio. Reads poly-A selected paired-end reads). Paired end sequencing of both DNA strands from each end is required for fragment strand specificity.