Overview

Homology-directed repair (HDR) is a natural DNA repair mechanism in cells that uses a homologous sequence as a template to repair double-strand breaks (DSBs). 

One powerful application of CRISPR/Cas genome editing technology involves utilizing HDR for the precise insertion (or ‘knock-in’) of a DNA sequence into a targeted site to introduce a specific genetic modification. DNA donor templates, or HDR templates, can be designed with the desired genetic modifications and produced at scale.

While many factors may affect the efficacy of this approach, choosing the right HDR template is a critical step. GenScript offers high-quality, sequence-verified HDR templates in both linear and circular formats to maximize the editing efficiency of your CRISPR experiments and support a variety of non-viral applications, including cell therapy and gene therapy development. 

Ready to get started? Access our intelligent GenCRISPR HDR Knock-in Design Tool to easily design HDR templates (up to 20 kb!) and guide RNA, ranked by algorithmic scores for compatibility:

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What template formats are available?

GenExact™ ssDNA
Precise KI and low cytotoxicity
GenExact ssDNA

Application

Ideal for T cell therapy

Ideal for cell/animal model generation

Advantages

Minimal cytotoxicity

Precise knock-in, minimized off-target effects

High purity and sequence-verified

Specifications

Insertion length: 200*-6,000 nt

µg to mg scale

Research to cGMP grade

*We also offer <200 nt ssDNA through our DNA Oligo Synthesis Service.

GenWand™ dsDNA
Long gene knock-in in large scale

Application

Ideal for long gene CRISPR KI

Ideal for screening and scale-up

Advantages

Covalently closed ends protect for better accuracy

More suitable for scale-up

High purity and sequence-verified

Specifications

Insertion length: 1-10 kb

µg to g scale

Research to cGMP grade

GenCircle™ dsDNA
Circular template with no resistance gene

Application

Ideal replacement for plasmid HDR template

Ideal for scale-up and fast delievery

Advantages

KI efficiency increase by up to 30%

429bp backbone, lower cytotoxicity & higher transfection efficiency

No antibiotic resistance avoids regulatory concern

High purity and sequence-verified

Specifications

Insertion length: 1-20 kb

µg to g scale

Research to cGMP grade

Non-viral CAR-T Knock-in Optimization Kits

Save time optimizing your CAR insertion process
with pre-validated sequences, design and protocols.

Resources

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