Page 102 - PCC08

Gene repair. Human 3PN Model
• CRISPR/Cas9 can cleave the endogenous β-globin gene (HBB)
• The efficiency of homologous recombination directed repair (HDR) of HBB is low and the edited embryos were mosaic.
• Off-target cleavage was also apparent in these 3PN zygotes.
• Repair of the HBB locus occurs preferentially through the non- crossover HDR pathway.
• Need to further improve the fidelity and specificity of the CRISPR/Cas9 platform, a prerequisite for any clinical applications of CRSIPR/Cas9- mediated editing.
CRISPR/Cas9-mediated gene editing in human tripronuclear zygotes PCC Genetics - ESHRE BCN 2018
Gene insertion. Human 3PN Model
Results By co-injecting Cas9mRNA, gRNAs, and donorDNA, successful introduction of the naturally occurring CCR5Δ32 allele into early human 3PN embryos.
In the embryos containing the engineered CCR5Δ32 allele, the other alleles at the same locus could not be fully controlled because they either remained wild type or contained indel mutations.
Introducing precise genetic modifications into human 3PN embryos by CRISPR/Cas 9- mediated genome editing JARG, Kang, 2016
PCC Genetics - ESHRE BCN 2018
Targeted editing of the HBB gene in human 3 PN zygotes by intracytoplasmic injection
Protein Cell, Liang,2016
Page 96 of 102
102