Precise excision of HTLV-1 provirus with a designer-recombinase.

Area of Science:

• Molecular Virology
• Genome Editing
• Antiviral Therapy

Background:

• Human T-cell leukemia virus type 1 (HTLV-1) is a pathogenic retrovirus causing adult T-cell leukemia (ATL), an aggressive and incurable cancer.
• Over 10 million people are infected globally, with 5% developing ATL.
• Genome editing tools offer potential as novel antiviral strategies.

Purpose of the Study:

• To engineer site-specific recombinases for the excision of the HTLV-1 proviral genome from infected cells.
• To evaluate the efficacy of a designer-recombinase in reducing HTLV-1 proviral load.

Main Methods:

• Utilized substrate-linked directed evolution (SLiDE) to engineer Cre-derived recombinases.
• Identified a conserved loxP-like sequence (loxHTLV) in HTLV-1 long terminal repeats.
• Isolated and characterized a designer-recombinase (RecHTLV) for loxHTLV recombination in bacterial and human cells.

Main Results:

• Engineered RecHTLV demonstrated efficient and specific recombination of the loxHTLV sequence.
• RecHTLV expression conferred antiviral activity against HTLV-1 in Jurkat T-cells.
• Expression of RecHTLV led to the successful excision of HTLV-1 proviral DNA in chronically infected cells.

Conclusions:

• Recombinase-mediated excision of the HTLV-1 provirus is a viable strategy to reduce proviral load.
• This approach holds promise for preventing HTLV-1-associated diseases, including ATL.
• Further development of genome editing tools could offer new therapeutic avenues for HTLV-1 infection.