 scaffold variants for use in mammalian genome editing.){kind=link}
A study introduces a large, systematically characterized collection of polymerase III promoter and guide RNA (gRNA) scaffold variants for use in mammalian genome editing. These components offer a way to achieve more predictable and tunable control over CRISPR-based editing in mammalian cells.
The researchers developed a multiplex prime editing assay that allowed thousands of promoter and scaffold sequences to be tested in parallel. This approach provided quantitative measurements of both editing efficiency and RNA abundance, enabling comparisons across human and mouse cell lines. Many of the newly designed parts showed consistent activity across different genomic targets and cell contexts, and a substantial number performed better than the commonly used standard sequences.
The work combines sequence mining, rational design, and mutagenesis to expand the diversity of usable parts. The resulting promoters and scaffolds span several orders of magnitude in activity, allowing finer adjustment of gene editing rates. Because promoter variants modulate transcription rather than target-specific interactions, they may be particularly useful for applications that require general, predictable control of RNA expression.
The array’s performance matched predictions based on individual part activity, highlighting the potential for building complex and quantitatively tunable genetic systems from these standardized components.
The collection provides a foundation for future applications in multiplexed genome perturbation, lineage tracing, and genetic circuit design. By offering a quantitative framework for part performance, the study moves toward making mammalian genome engineering more systematic and reproducible, similar to the established approaches in microbial systems.