Rational Design of ssODN to Correct Mutations by Gene Editing

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Olga V. Volodina¹, Arina A. Anuchina¹, Milyausha I. Zainitdinova¹, Nadezhda A. Evtushenko², Alexander V. Lavrov¹, and Svetlana A. Smirnikhina^1,a*

¹Research Centre for Medical Genetics, 115522 Moscow, Russia

²Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Pirogov Russian National Research Medical University, 117997 Moscow, Russia

^* To whom correspondence should be addressed.

Received December 3, 2021; Revised April 19, 2022; Accepted April 19, 2022

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Gene editing allows to make a variety of targeted changes in genome, which can potentially be used to treat hereditary human diseases. Despite numerous studies in this area, effectiveness of gene editing methods for correcting mutations is still low, so these methods are not allowed in routine practice. It has been shown that rational design of genome editing components can significantly increase efficiency of mutation correction. In this work, we propose design of single-stranded oligodeoxyribonucleotides (ssODNs) to increase efficiency of gene editing. Using a model system to repair knocked out EGFP that is integrated into the genome of HEK293T cell culture, we have shown that only a small part of ssODN (about 20 nucleotides: from the 15th nucleotide at 3′-end to the 4th nucleotide at 5′-end), a donor molecule for repairing double-stranded DNA breaks, is integrated into the site of the break. Based on the obtained data, it is possible to rationally approach the design of ssODNs to correct mutations using CRISPR-Cas9 method for the development of gene therapy for hereditary human diseases.

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KEY WORDS: CRISPR-Cas9, single-strand template repair, single-stranded oligodeoxyribonucleotides, EGFP, flow cytometry

DOI: 10.1134/S0006297922050078

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