I want to study some features of human miRNAs. I need more lengths at 5' & 3' ends for each miRNA concerning the data provided by the miRBasewww.mirbase.org). For example for hsa-mir-6723 the miRBase has provided followed sequence: 5'-AUGCAUCGGGAUAGUCCGAGUAACGUCGGGGCAUUCCGGAUAGGCCGAGAAAGUGUUGUGGGAAGAAAGUUAGAUUUACGCCGAUGAAU-3' As you may know this is called "pre-miRNA" which after some splicing, it produces functional miRNA which is called mature miRNA (From 11-32). I want 100 nucleotides more in upstream and downstream of this pre-miRNA. By use of this miRNA's coordination ,chr1: 567705-567793 [-], and use of the Table Browser (http://genome.ucsc.edu/cgi-bin/hgTables) I got its DNA sequences (by add 100 nucleotides more in upstream and downstream). Finally I replaced its DNA nucleotide symbols by RNA symbols simply for further analysis. I'm not sure about the accuracy of this method and I'm going to do this for hundreds of miRNAs. Would you please give me some kind advice.
Thanks in advance; Esmaeel