Tome launches CRISPR tool for oversized DNA

Tome Biosciences has debuted with $213 million to bring their genome-editing platform to the clinic. The technology can insert large DNA sequences into the genome in any position to correct

genes in vivo. The tool, dubbed PASTE — programmable addition via site-specific targeting elements — was developed by Tome co-founders Omar Abudayyeh and Jonathan Gootenberg from the

Massachusetts Institute of Technology. Investors include Andreessen Horowitz, Arch Venture Partners, Polaris and Fujifilm.

PASTE uses a CRISPR–Cas9 nickase fused with two other enzymes: a reverse transcriptase and a serine integrase. The guide RNA-directed reverse transcriptase creates landing sites for the

serine integrase, which inserts large sequences of DNA. Tome has shown that its tool can insert sequences of ~36 kb in various dividing and non-dividing cell types. And, unlike other editing