Functional characterization of the active Mutator-like transposable element, Muta1 from the mosquito Aedes aegypti

Area of Science:

• Genetics
• Molecular Biology
• Transposable Elements

Background:

• Mutator-like transposable elements (MULEs) are globally distributed across diverse organisms.
• Research has primarily focused on plant MULEs due to their high activity and impact on genome structure.
• Few active MULEs have been identified, with limited evidence of activity outside their native host.

Purpose of the Study:

• To identify and characterize potentially active MULEs in the mosquito Aedes aegypti.
• To investigate the transposition capabilities of the identified Muta1 element in a heterologous system.
• To elucidate the functional importance of conserved amino acids and target site duplications in MULE transposition.

Main Methods:

• Identification of MULEs in Aedes aegypti.
• Utilized a yeast transposition assay to test Muta1 excision and reinsertion.
• Performed site-directed mutagenesis on the Muta1 transposase and donor site target site duplications.

Main Results:

• Identified potentially active MULEs in Aedes aegypti, including Muta1.
• Demonstrated Muta1's ability to undergo excision and reinsertion in yeast, generating 8 bp or 9 bp target site duplications (TSDs).
• Showed that donor site TSDs are crucial for precise excision and enhanced transposition, and that conserved amino acids, including the DDE catalytic motif, are essential for transposase function.

Conclusions:

• The Muta1 transposase from Aedes aegypti exhibits efficient catalytic activity for both excision and reinsertion in a yeast system.
• Conserved amino acids, notably the DDE triad, are critical for Muta1 transposase function.
• Donor site target site duplications significantly influence the transposition process of Muta1.