| Modification Notes |
Group I intron-encoded endonucleases, like I-SceI, represent a new class of double strand cutting endonucleases which generate double strand breaks in site-specific sequences (1,2). Despite its small size, I-SceI initiates intron homing by recognizing and specifically cleaving a large intronless DNA sequence (3). I-SceI binds to its substrate in monomeric form (3). The I-SceI restriction site is absent from most prokaryotic and eukaryotic genomes (4). The mitochondrial I-SceI has an 18-bp recognition sequence and, therefore, has a very low probability of cutting DNA, even within large genomes (5). Double-strand breaks can be initiated by the I-SceI endonuclease at a predetermined location in the genome and the breaks can be repaired with a donor molecule homologous regions flanking the breaks (5). |