Engineered Moloney Murine Leukemia Virus reverse transcriptase (M-MLV RT)

The engineered reverse transcriptase (RT) is a central enzymatic component of the prime editor (PE) complex, a versatile genome editing tool described as a "search-and-replace" system (Anzalone et al., 2019, Nature). Typically derived from the Moloney Murine Leukemia Virus (M-MLV), the RT is modified with specific mutations—such as D200N, L603W, T330P, T306K, and W313F—to improve its thermostability, processivity, and DNA-RNA binding affinity (Anzalone et al., 2019; Chen et al., 2021, Cell). In the prime editing architecture, the RT is fused to a catalytically impaired Cas9 nickase (H840A) and guided by a prime editing guide RNA (pegRNA). The RT synthesizes new DNA by extending the 3' end of the nicked genomic DNA strand using the pegRNA's extension as a template, thereby introducing precise genetic modifications including point mutations, insertions, or deletions (Prime Medicine, 2024). This mechanism bypasses the need for double-strand breaks or exogenous donor DNA, potentially reducing the risk of unwanted genomic rearrangements compared to traditional CRISPR-Cas9 systems (Petri et al., 2021, Nature Communications). Therapeutic applications focus on correcting pathogenic mutations in genetic diseases like sickle cell disease and various metabolic disorders (Prime Medicine, 2024).

Other names

PE-RTPrime editor reverse transcriptaseEngineered M-MLV RTM-MLV RT (D200N/L603W/T330P/T306K/W313F)

The engineered reverse transcriptase synthesizes a new DNA strand using the 3' extension of the prime editing guide RNA (pegRNA) as a template, incorporating the desired genetic change into the target genomic locus (Anzalone et al., 2019, Nature).