Editing Sites Identification And Formation Mechanism Study Of The A To I Editing Of Invertebrates Kv2 Gene

The molecular mechanism and physiological function of recoding by A-to-I RNA editing is well known, but its evolutionary significance remains a mystery. The RNA editing of the Kv2 K~+channel from different classes of Arthropoda are extensively analyzed. By comparing the RNA RT-PCR sequence with the genomic sequence, we verify several editing sites that change codon usage within exon 2. It is notable that three of these editing sites were conserved in most species, suggesting that a crucial role of function during hundreds of millions of years' evolution. We also found that in the same classis, different species share identical editing sites, meantime own their specific editing sites. We all know that the occurrence of RNA editing is catalyzed by the ADAR enzyme family. Their editing substrates are RNA stem-loop structures that are occasionally formed by an exon sequence and an inverted repeat located in the downstream intron. Surprisingly, bioinformatical analysis of B.mori, D. melanogaster and A.mellifera kv2 RNA secondary structures show that the entire exon 2 sequence form a perfect double-stranded RNA structure that could be the editing substrate. Although it has been found in mammals Kv1.1 and Gabra-3 before, it is still rare that the editing sites and the editing complementary sequences are located in the same exon. Based on these results, experiments are undertaken to demonstrate our predictions. However, the results show that only D. melanogaster can be edited.