EMS Mutation and SNP Detection in Intracellular Wolbachia Genomes

Area of Science:

• Microbiology
• Genetics
• Bioengineering

Background:

• Endosymbiotic bacteria like Wolbachia present challenges for genetic study due to their intracellular nature.
• Current protein function understanding relies on homology, which may not reflect in-host roles.
• Genetic manipulation tools are crucial for advancing bioengineering with intracellular symbionts.

Purpose of the Study:

• To demonstrate the successful application and detection of chemical mutagenesis in the Wolbachia genome.
• To establish a method for detecting low-frequency mutations in intracellular bacterial populations.
• To provide a foundation for future targeted genetic edits in Wolbachia.

Main Methods:

• Chemical mutagenesis of the w Mel strain of Wolbachia within Drosophila melanogaster JW18 cells using ethyl methanesulfonate (EMS).
• Ultra-low error rate sequencing strategy, specifically circle sequencing, to detect low-frequency EMS-induced mutations.
• Analysis of mutation patterns, focusing on C/G>T/A transitions, and modeling mutation rates across genomic contexts.

Main Results:

• Successfully applied EMS mutagenesis to the Wolbachia genome within a host cell line.
• Circle sequencing enabled confident detection of EMS-induced single nucleotide polymorphisms (SNPs).
• Observed a significant enrichment of canonical C/G>T/A transitions, confirming EMS activity.
• Developed a model for EMS mutation rates across different genomic sequence contexts.

Conclusions:

• EMS treatment can generate detectable mutation signals within intracellular bacterial genomes like Wolbachia.
• Circle sequencing is a powerful tool for detecting low-frequency mutations in unsorted cell populations.
• These findings pave the way for developing targeted genetic editing protocols for Wolbachia.