Instrument: AB 5500xl Genetic Analyzer
Strategy: RNA-Seq
Source: TRANSCRIPTOMIC
Selection: cDNA
Layout: SINGLE
Construction protocol: RNA was extracted with the SPLIT RNA extraction kit (Lexogen GmbH, Vienna, Austria) yielding the large RNA fraction with a lower cut-off size of 150 nt. Evaluation on an Bioanalyzer RNA Nano chip (Agilent Technologies) showed medium to high RNA quality (RIN of 6.2 – 8.3). Briefly, 4 µg Terminator-treated RNA was full-length reverse transcribed, and 1/20th of the purified cDNA was then amplified in one of 12 parallel PCR reactions. Each PCR reactions was set up with one universal 5’ primer and a 3’ primer selective for one of the 12 possible combinations of the two terminal nucleotides of the mRNA body, immediately upstream of the poly(A) tail. 200 ng of all 288 PCR products (24 RNA samples amplified separately in 12 matrix fields) were heat-fragmented and then ligated to SOLiD-compatible adapters. The libraries were PCR amplified in 17 cycles, with PCR primers indexing each sample with one out of 96 bar-codes. Three lane mixes were created, each from 96 libraries corresponding to 24 samples amplified in 4 matrix fields, dedicating equal molarities to each of the libraries. The three lane mixes SOR04 (selective 3’ primer nucleotides AC, AG, CA, GT), SOR05 (AA, AT, CC, CG) and SOR06 (CT, GA, GC, GG) were then further size-selected on a Pippin Prep automated gel elution system (Sage Biosciences, Beverly, MA, USA) in the range of 170 to 400 bp.