Revision as of 12:14, 2 October 2024

DNA fragment for CFTR-specific pegRNA screening

Introduction

In the context of cystic fibrosis, the F508del mutation represents a significant challenge for correction. The efficacy of current gene editing technologies hinges on the availability of precise tools to ensure the success of treatment strategies. In view of the above, we have developed a novel reporter system that is specifically tailored to the F508del mutation in the CFTR gene. The objective is to provide a high degree of comparability to the genomic context of this mutation, while maintaining ease of use. This system allows researchers to test and screen Prime Editors and various pegRNAs (prime editing guideRNAs), particularly in the context of the F508del mutation. By closely mimicking the genomic environment, it is believed that this tool will offer enhanced utility in the selection of optimal Prime Editing strategies.

Design and Functionality

The reporter system has been designed with the specific intention of facilitating a more comparable genomic context for the F508del mutation, particularly for the purpose of testing the efficacy of different pegRNA variants and prime editors. The system provides a highly reliable platform for screening a variety of pegRNAs, thereby facilitating the identification of the most effective variant for correcting the F508del mutation. The system is constructed around a plasmid structure, specifically pDAS12124_PEAR-GFP-GGTdel, from which a modified version of GFP (Green Fluorescent Protein) has been derived. The green fluorescent protein (GFP) is composed of two exons, separated by a Vim gene intron in its natural state. In the absence of the intron, the GFP is expressed and fluoresces. However, the GFP sequence was modified to introduce a three-base-pair deletion, specifically in the junction between Exon 1 and the Vim gene intron. This deletion affects the last base of Exon 1 and the first two bases of the intron, effectively disrupting the splice site. As a result, the intron is no longer correctly spliced out, leading to the expression of a non-functional GFP that does not fluoresce.

Functionality in Prime Editor and pegRNA testing

The principal feature of the reporter system is its capacity to assess and quantify the efficacy of diverse Prime Editors, with a particular focus on pegRNAs. In its default state, the system expresses a non-functional GFP due to the disruption of the splice site. However, if a Prime Editor successfully restores the mutation to its correct form, the splice site is repaired and functional GFP is expressed, thereby allowing for fluorescent detection. This fluorescence serves as a reliable indicator of successful prime editing.

Conclusion

This reporter system represents a substantial advancement in the study and correction of the CFTR F508del mutation. The design of the system allows for the straightforward screening of an array of Prime Editor and pegRNA constructs, while maintaining a high degree of comparability to the genomic context. By closely emulating the CFTR gene environment, particularly in the context of the F508del mutation, researchers are able to identify the most efficient pegRNAs and Prime Editors, offering a promising approach for developing more effective gene-editing treatments for cystic fibrosis.

Sequence and Features