Mixed Wolbachia Infections in Drosophila Cell lines

Alexandra Lum

Mentor: Shelbi Russell

Department of Biomolecular Engineering

Introduction

What is Wolbachia?

bacterial symbiont that lives inside the cells of ~60% of known insect species
needs to live inside host cells to survive

wMel

strain of Wolbachia native to Drosophila melanogaster (temperate)
"faithful" to the host organism with high germline affinity

wWil

strain of Wolbachia native to Drosophila willistoni (tropical)
"faithful" to the host organism with high germline affinity

The trait of germline affinity is shared, but is more prevalent in wWil

Goal: Figure out which strain is a better symbiont!

Methods

Drosophila cell culture (cell lines: JW18, S2, Dsim6B)
sequencing (short-read)
Wolbachia coverage workflow

Create Cell Mixtures

For each cell line, create 3 replicates of each ratio (1:1, 1:100, 1:1K)

Sample and Maintain

Split in half to a new flask and sample some cells!

Sequence Samples

Illumina sequencing using a Tn5 library preparation method

Filter Reads

Align Reads

Calculate Depths

Graph Titer

Snakemake Pipeline

Results

Mirchandani et al. 2024

Discussion

more signal and less deterministic than wMel (faithful) vs wRi (promiscuous) in Mirchandani et al. 2024
clear distinctions between cell lines suggests complex molecular mechanisms based on cell type (neuroblast vs macrophage, etc)
thus far, media type appears to have no impact despite significant visual phenotypic differences (adherence vs non-adherence) and stable titer differences
Long term coexistence and oscillating pattern in JW18 cells suggests the existence of multiple intracellular symbiotic niches

References

[1] C. Mirchandani et al., “Mixed Wolbachia infections resolve rapidly during in vitro evolution,” Mar. 29, 2024, bioRxiv. doi: 10.1101/2024.03.27.586911.

S L Russell, unpublished

Acknowledgements

Thank you to Shelbi Russell for her mentorship as well as the other members of the Russell Lab for their support and assistance. This project utilized the Phoenix computational cluster provided by the UCSC Genomics Institute.

Funding Sources: Koret Foundation; NIH R00GM135583, SLR; NIH R35GM157189, SLR

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