RNA EDITING GENERATES A DIVERSE ARRAY OF TRANSCRIPTS ENCODING SQUID KV2 K-PROPERTIES( CHANNELS WITH ALTERED FUNCTIONAL)

We have cloned a Kv2 potassium channel from squid optic lobe termed sq Kv2. Multiple overlapping sqKv2 cDNA clones differed from one another at specific positions by purine transitions. To test whether the purin e transitions were generated by RNA editing, we compared a 360 nucleot ide genomic sequence with corresponding cDNA sequences (encoding S4-S6 ) isolated from individual animals and lying on a single gene and exon . cDMA sequences differed from genomic sequence at 17 positions, resul ting in 28 unique sequences. There was invariantly an adenosine in the genomic sequence and a guanosine in the edited cDNA sequences. Two of the edits altered the rates of channel closure and stow inactivation. These results extend selective RNA editing to invertebrate taxa and r epresents a novel mechanism for the posttranscriptional modulation of voltage-gated ion channels.