Measuring TREX1 and TREX2 exonuclease activities

Area of Science:

• Molecular Biology
• Immunology
• Genetics

Background:

• Three-prime Repair Exonuclease (TREX1) degrades single-stranded DNA (ssDNA) and double-stranded DNA (dsDNA).
• TREX1 prevents autoimmune diseases by degrading cytosolic DNA, thus inhibiting aberrant nucleic acid sensing and immune activation.
• Mutations in TREX1 are linked to human autoimmune conditions like Aicardi-Goutières syndrome and lupus.

Purpose of the Study:

• To describe methods for purifying variant recombinant TREX1 enzymes.
• To outline assays for measuring TREX1 exonuclease activity on ssDNA and dsDNA substrates.
• To explore the relationship between TREX1 activity, mutation types, and associated autoimmune diseases.

Main Methods:

• Purification of variant recombinant TREX1 enzymes.
• Exonuclease activity assays using ssDNA and dsDNA substrates.
• Analysis of over 60 identified disease-causing TREX1 variants.

Main Results:

• Established methods for assessing the exonuclease activity of TREX1 variants.
• Demonstrated that TREX1 mutations impact enzymatic activity.
• Considered the correlation between specific TREX1 mutations, altered activity, and disease phenotypes.

Conclusions:

• TREX1 exonuclease activity is critical for preventing autoimmune disorders.
• Characterizing TREX1 variants and their enzymatic function is essential for understanding TREX1-associated diseases.
• The described methods facilitate research into the molecular basis of TREX1-related autoimmune conditions.