Profiling Thermus thermophilus Argonaute Guide DNA Sequence Preferences by Functional Screening

Area of Science:

• Molecular Biology
• Biochemistry
• Genetics

Background:

• Prokaryotic Argonautes (pAgo) are guided endonucleases crucial for nucleic acid processing.
• Understanding how pAgo generates guides in vivo is key to their application.
• Thermus thermophilus Argonaute (TthAgo) has shown specific sequence and structural preferences for guide selection.

Purpose of the Study:

• To functionally characterize guide sequence preferences in T. thermophilus Argonaute.
• To identify sequence features that improve guide design for molecular applications.
• To establish criteria for creating efficient guides for TthAgo.

Main Methods:

• Screening of 1,968 guides against randomized DNA substrates.
• Quantification of endonuclease activity using high-throughput capillary electrophoresis.
• Identification of localized sequence preferences influencing guide efficiency.

Main Results:

• A strong cleavage enhancement was observed with a first position dT, irrespective of the target sequence.
• Activity significantly decreased with dA at position 12.
• GC dinucleotides at positions 10 and 11 impacted endonuclease activity.

Conclusions:

• The study identified specific sequence preferences for T. thermophilus Argonaute guide selection.
• These findings provide criteria for designing more efficient guides for molecular applications.
• The method can be expanded to characterize other pAgo variants for broader utility in genome editing.