Figure 1

Amplification primers. A: Alternative primers used during miRNA sequencing library preparation to make the SREK protocol compatible with the Illumina Genome Analyzer. * Indicates a phosphorothioate bond. B: Library fragment separation on a 6% PAGE gel. Different library fragment sizes can be discerned which represent different types of RNA ligated in between the SREK adapters as indicated at the left of the gel. Due to the length of the alternative primers used during library amplification, the size of an empty library fragment is 125 bp. The miRNA fraction of the library is located at 140-150 bp.