Multiple alignment of MER53-derived miRNAs from miRBase v13.0 and the secondary structures of MER53 elements. (A) The multiple alignment of MER53 and the eight identified MER53-derived sequences of hsa-mir-1302. (B) The secondary structure of an MER53 element showing its palindromic stem-loop structure. The MER53 element was retrieved from the RepeatMasker Database. (C) An example of the secondary structure of an MER53 element that harbors the precursor and mature sequence of hsa-mir-1302-6. The hairpin structure of the precursor of hsa-mir-1302-6 is shown in red and the segment corresponding to the mature miRNA is highlighted in light blue.