FIGURE 3.

RNA editing of SR-protein SRp25 in the human brain. (A) Sequence analysis of paired SRp25 genomic DNA (control) and brain cDNA of the same human brain specimen. Electropherograms show the antisense sequence of exon 3 in SRp25 around the predicted editing site. A mixed peak of T and C in the cDNA sample but not in the genomic counterpart indicates the presence of two populations of molecules. Subcloning of the same PCR amplicon used for sequencing revealed an editing level of 7%. (B) Amino acid change caused by RNA editing modification. A section of the open reading frame within exon 3 of SRp25 is shown with the K-to-R codon alteration indicated. (C) Computer-predicted RNA secondary structure of the SRp25 pre-mRNA sequence. A partially double-stranded RNA hairpin consisting entirely of exon 3 sequences is shown with the main editing site (highlighted in red and underlined) as well as potential additional sites (underlined) indicated.