CRISPR Homology-Directed Repair (HDR) Knock-in Templates

The precise insertion of DNA sequences using the homology-directed repair (HDR) pathway is one potential use of the CRISPR/Cas genome editing technology. Various circumstances could influence the effectiveness of this strategy, but picking the appropriate HDR template is undoubtedly crucial.

GenScript now provides high-quality, sequence-verified HDR templates to help users edit their CRISPR experiments more effectively.

CRISPR HDR knock-in templates

Accurate and minimally hazardous ssDNA GenExact™ for effective CRISPR KI

CRISPR Homology-Directed Repair (HDR) knock-in templates

Image Credit: GenScript

  • Appropriate for constructing animal models
  • Suitable for T-cell therapy

Large-scale long gene knock-in using closed-end GenWand™ dsDNA.

CRISPR Homology-Directed Repair (HDR) knock-in templates

Image Credit: GenScript

  • Ideal for screening and scale up
  • Ideal for long-gene CRISPR KI

GenExact™ ssDNA

  • Precise knock-in, minimized off-target effect
  • Research to cGMP grade
  • 150–5000 nt
  • High purity and sequence verified
  • µg to mg scale
  • Minimal cytotoxicity

GenWand™ dsDNA

  • µg to g scale
  • Research to cGMP grade
  • More suitable for scale-up
  • High purity and sequence verified
  • Covalently closed ends protection for better accuracy
  • 2–10 kb


Highly efficient non-viral T cell engineering process at clinical scale with GenExact™ ssDNA

Collaboration with UCSF’s (University of California San Francisco) Marson’s lab revealed that:

  • At a GMP-compatible scale, the KI efficiency of GenExact™ ssDNA through electroporation without any enhancer can reach 46.2%
  • GenExact™ ssDNA produced much higher KI-positive live cells than the patient’s projected dose (100*10e6). BCMA-CAR cells were effectively killed in in vitro experiments
  • When compared to internally produced HDRTs (homology-directed repair templates), GenExact™ ssDNA consistently outperformed them due to its lower levels of toxicity and higher knock-in efficiency

CRISPR Homology-Directed Repair (HDR) knock-in templates

Brian R Shy. et al., bioRxiv(2021). Image Credit: GenScript

GenWand™ dsDNA outperforms PCR products in knocking in larger genes

Comparing GenWandTM dsDNA to internal PCR dsDNA (38% vs. 21%), the KI efficiency was found to be 80% higher.

CRISPR Homology-Directed Repair (HDR) knock-in templates

GFP KI at RAB11A Locus in HEK293 cells using electroporation with 5 ug of PCR dsDNA and GenWand™ dsDNA templates. Image Credit: GenScript