Header and Body 2

Problem Addressed

Application of CRISPR-Cas gene-editing tools without the need for repair-pathway dependent editing in mammalian cells is challenging because it requires the expression and delivery of as many as 4-7 proteins to the nucleus for proper assembly and DNA targeting. Furthermore, the ability to use Cas9 and Cas12 nucleases in CRISPR-Cas gene editing systems in vivo or ex vivo is hindered by their size, which can be as many as 1000 amino acids long. Therefore, technologies that edit or program the activation or inhibition of genes based on these nucleases cannot typically be delivered to mice by known viral vectors including the therapeutically validated adeno-associated vectors (AAV) because of their restricted size capacity (<5 kb). Smaller CRISPR-associated nucleases described here would allow for simpler delivery and extended CRISPR applications by enabling delivery of the nuclease and guide RNA in a single vector.