Occurrence of tetranucleotides motifs connected with hairpin formation in human miRNA sequences.

The all miRNAs with the ability to form secondary structure were subjected to the analysis. The searching was performed according to: first—motifs present in loop of the predicted hairpins, second: motifs present in the loop where at least 3 base pair were predicted in the stem and finally-where at least 3 base pair and additionally C-G as a closing pair in the stem were predicted.