Enhancing Prime Editing Efficiency Through Modulation of Methylation on the Newly Synthesized DNA Strand and Prolonged Expression.

Prime editors (PEs) have emerged as transformative tools for precision genome engineering, yet their broader application remains constrained by incomplete understanding of repair mechanisms. In this study, it is found that an increase in the methylation level of the CpG sequence on the newly generated strand can increase PE efficiency and that de novo DNA methyltransferases (DNMT3A/3B) are involved in the PE repair pathway. On the basis of these novel findings, the development of an episomal element-driven PE system (epiPE) achieved through the use of EBNA1/oriP are presented, which increases methylation levels around target sites and prolongs PE expression.

EXPERT expands prime editing efficiency and range of large fragment edits.

Prime editing systems (PEs) hold great promise in modern biotechnology. However, their editing range is limited as PEs can only modify the downstream sequences of the pegRNA nick. Here, we report the development of the extended prime editor system (EXPERT) to overcome this limitation by using an extended pegRNA (ext-pegRNA) with modified 3' extension, and an additional sgRNA (ups-sgRNA) targeting the upstream region of the ext-pegRNA.

CRISPR-Cas9-Mediated Cytosine Base Editing Screen for the Functional Assessment of Intron Variants in Japanese Encephalitis Virus Replication.

The Japanese encephalitis virus (JEV) is a mosquito-borne flavivirus that causes viral encephalitis in humans, pigs and other mammals across Asia and the Western Pacific. Genetic screening tools such as CRISPR screening, DNA sequencing and RNA interference have greatly improved our understanding of JEV replication and its potential antiviral approaches. However, information on exon and intron mutations associated with JEV replication is still scanty.