Transcript Level and Sequence Matching Are Key Determinants of Off-Target Effects in RNAi

Area of Science:

• Agricultural Science
• Molecular Biology
• Biotechnology

Background:

• RNA interference (RNAi) using double-stranded RNA (dsRNA) shows promise for pest control.
• Off-target effects of dsRNA limit RNAi applications and raise ecological concerns.
• Understanding the factors influencing dsRNA off-target effects is crucial for safe implementation.

Purpose of the Study:

• To investigate the key factors regulating off-target effects of dsRNA in RNAi-based pest control.
• To determine the relationship between gene expression levels, sequence identity, and dsRNA efficacy.
• To provide guidelines for designing more specific and efficient dsRNA pesticides.

Main Methods:

• Analysis of dsRNA off-target effects in relation to target gene transcript levels.
• Determination of critical sequence identity thresholds for off-target binding.
• Evaluation of contiguous matching sequence length and mismatch tolerance.
• Assessment of dsRNA dosage impact on off-target effects.

Main Results:

• Off-target effects are regulated by both transcript level and sequence matching.
• Lower expressed genes show reduced knockdown compared to highly expressed genes.
• A critical sequence identity of approximately 80% was identified.
• Off-target effects are triggered by contiguous matches >15 nt or near-perfect matches with 1-2 mismatches >19 nt.
• Increased dsRNA dosage exacerbates off-target effects.

Conclusions:

• Transcript level and sequence characteristics are key determinants of dsRNA off-target effects.
• Specific sequence length and identity parameters can predict and mitigate off-target binding.
• Findings facilitate the rational design of selective dsRNA pesticides for improved RNAi efficacy and safety.