Integrated DNA Technologies (IDT) has released Alt-R HDR Donor Blocks, a solution for increasing homology-directed repair (HDR) rates in large fragment knock-in experiments.
How does Alt-R HDR work?
The Alt-R HDR Donor Blocks incorporate advanced chemical modifications to boost the HDR rates of large genomic changes and insertions, and significantly reduce the occurrence of non-homologous (blunt) integration of the donor sequence.
In a study, IDT investigated the impact on HDR efficiencies when inserting a green fluorescent protein tag using long, single-stranded DNA (ssDNA) or double-stranded DNA (dsDNA) templates. The outcomes demonstrated that the use of Alt-R HDR Donor Blocks resulted in the highest HDR rates compared to unmodified dsDNA or long ssDNA.
The ability of Alt-R Donor Blocks to reduce the occurrence of unwanted off-target integrations was also investigated. In addition, results showed a 65% reduction in blunt insertions at a mock off-target double-strand break compared to unmodified dsDNA.
“It is well established that a key challenge in precise genome editing research is the low efficiency of HDR rates, and our new solution is singularly focused on helping researchers make HDR experiments more efficient and more likely to succeed,” said Mark Behlke, IDT’s Chief Scientific Officer. “Alt-R HDR Donor Blocks are the latest examples of products resulting from extensive wet-bench research conducted by IDT’s R&D scientists. We hope this new product can help increase research yields for the scientific community and serve as a gateway to repairing disease-causing mutations, altering genomes, and enabling more discoveries.”
Ann Morris, an Associate Professor at the University of Kentucky, added: “We worked with IDT on a project to generate knock-in zebrafish carrying an in-frame epitope tag in our gene of interest. In-frame knock-ins are notoriously difficult to obtain in zebrafish, but IDT helped us design several candidate donor templates with various modifications to determine which one would work best. The IDT Alt-R HDR Design Tool was easy to work with, and we were able to rapidly test several permutations of HDR donor blocks to successfully obtain our desired knock-in line. IDT staff gave us a lot of helpful advice, and were readily available throughout the process to answer our questions and get feedback on what worked best. We will definitely work with them again on our next knock-in project.”