22-bp pseudo-palindromic I-CreI recognition site (I-CreI target site)

The 22-bp pseudo-palindromic genomic DNA sequence recognized by I-CreI is the specific substrate for the I-CreI homing endonuclease, a member of the LAGLIDADG family originally identified in the chloroplast of the green alga Chlamydomonas reinhardtii (Chevalier et al., 2002). This DNA sequence is characterized by a near-symmetrical structure that allows the I-CreI homodimer to bind with high affinity and specificity, inducing a double-strand break (DSB) with 4-nucleotide 3' overhangs (Prieto et al., 2007). In its natural biological context, this interaction facilitates homing, a process where the endonuclease gene is inserted into an intron-less allele via homologous recombination. In the field of biotechnology, this 22-bp sequence serves as a foundational scaffold for the development of engineered meganucleases, such as those produced by the ARCUS platform, which are redesigned to target unique sequences within the human genome for therapeutic purposes (Smith et al., 2006). These engineered variants are utilized to treat genetic disorders and chronic viral infections by disrupting deleterious genes or facilitating precise gene insertions. The primary therapeutic challenge associated with targeting these sequences is ensuring high specificity to avoid off-target cleavage, which can lead to genotoxicity or chromosomal translocations.

Other names

I-CreI recognition sequence22-bp meganuclease targetChlamydomonas reinhardtii 23S rRNA intron sitePseudo-palindromic DNA target

Site-specific DNA double-strand break induction followed by cellular DNA repair mechanisms (NHEJ or HDR)