title: GSM1547681: E16.5 Morc1 het smRNA-seq; Mus musculus; miRNA-Seq
library_construction_protocol: Total RNA was isolated from embryonic testes using Ribozol. Thirty μg total RNA was loaded on 12% urea-polyacrylamide (PAA) gel. The 19-30 nt fraction was excised and snap-frozen in liquid nitrogen in 400 μl 0.4M NaCl. RNA was eluted from the gel overnight at 16°C while shaken at 1,000 rpm  and then precipitated with 3 vol absolute ethanol. Pre-adenylated 3’ linker (/5`Phos/TGGAATTCTCGGGTGCCAAGGAACTC/3`ddC/; 5’DNA adenylation kit, NEB) was ligated to RNA over night at 4C using Truncated RNA Ligase 2 (NEB). Ligation reactions were loaded onto 10% urea-PAGE, the 45-56 nt fraction was excised and nucleic acids extracted as above. 5’ linker (rGrUrUrCrArGrArGrUrUrCrUrArCrArGrUrCrCrGrArCrGrArUrC) was ligated to the samples using RNA Ligase 1 (NEB) over night at 4C. Ligation reactions were loaded on 10% Urea-PAA gel, 72-83 nt fraction was excised and nucleic acids as above. Extracted samples were reverse-transcribed (primer sequence: GGAGTTCCTTGGCACCCGAGA) and library amplified by PCR using standard Illumina primers. Final libraries were excised from the agarose gel and sequenced.  Since this is shaking, not centrifugation, we include rpm