GSM8322603: N2, 4C 1d, rep 1; Caenorhabditis elegans; RNA-Seq
Animals were washed off the plates with M9 buffer, followed by three washes with M9 buffer before being frozen in liquid nitrogen. Worms were lysed, monosomes purified and RNA was isolated using Trizol. The RNA from the monosomal fraction was separated using a 15% TBE-Urea Gel (Invitrogen) and the region around 28-30 nucleotides excised to isolate Ribosome protected fragments (RPFs). The gel piece was forced through a pierced small tube inside an eppendorf tube by centrifugation and RNA from the gel debris was eluted by overnight incubation in 600 µl cracking buffer (20 mM Tris-HCl (pH 7.9), 1 mM EDTA, 400 mM NH4Acetate, 0.5 % SDS). RNA was precipitated with isopropanol at -80 °C for at least 4 hours (isopropanol precipitation). RPFs were 3' dephosphorylated with 10 Units of T4 polynucleotide kinase (NEB) in T4 PNK buffer with 40 Units of RNasin for 1 hour at 37 °C. Following isopropanol precipitation, the RNA samples were ligated to 3' adapters according to the Illumina® TruSeq™ Small RNA Sample Preparation protocol and using the reagents of the kit, then again precipitated with isopropanol. Ligation products were 5' phosphorylated for 30 minutes at 37 °C with 15 Units of T4 polynucleotide kinase (NEB) in T4 PNK buffer, 1 mM ATP and 40 Units of RNasin. Following heat-inactivation of the enzyme for 10 minutes at 70 °C, the RNA was precipitated by isopropanol. Ligation to 5' adapters, reverse transcription, PCR amplification with barcoded primers and gel-purification of the PCR products were performed using the Illumina® TruSeq™ Small RNA Sample Prep kit. Four different barcodes (RPIX 2, 4, 5, 6) were used.