Research Opportunities

Quantitative imaging and pooled CRISPRi screening of single cells to understand transcription factor signaling dynamics. NF-κB is a master regulator of inflammation, immunity, and cell stress responses. The temporal dynamics of NF-κB signaling capture pathogen-specific information and govern the corresponding gene expression patterns. Recent studies have revealed that distinct NF-κB signaling profiles can lead to specific epigenetic modifications within potential enhancer regions of the genome, potentially establishing epigenetic memory for subsequent infections.

In this project, our goal is to investigate the impact of epigenetic perturbations on NF-κB signaling dynamics. We will utilize CRISPRi and a pool-genetic approach to systematically disrupt all potential enhancer regions around NF-κB-regulated genes. Additionally, we will conduct live-cell microscopy to quantitatively measure the resulting changes in NF-κB signaling dynamics. The insights gained from this study will illuminate the functions of the enhancer regions of NF-κB-regulated genes and will provide information on how tissue-specific NF-κB signaling is shaped by the epigenome, through the formation of epigenetic memories. The student will learn various interdisciplinary methods involving cell culture, quantitative microscopy, fluorescent reporter assays, automated single-cell analysis, molecular biology, and imaging data analysis.

Life thrives on collaboration – this extends to the molecular scale, where life is fueled by the chemical processes collectively called metabolism. Microorganisms exchange nutrients through cross-feeding, and multicellular organisms are made up of cells with different metabolic roles and needs. These collaborations allow for division of labour, for example between germline and soma.  Social insects provide an ideal study system to understand metabolic division of labour for two reasons:
1. They subvert the classic life-history trade-off between longevity and fecundity with long-lived highly fertile queens and small short-lived sterile workers, and
2. Many ant colonies engage in frequent mouth-to-mouth social exchanges of experimentally accessible fluids that contain endogenously produced materials.

These exchanges are so frequent that they form a social circulatory system that distributes material across the colony, allowing metabolic costs to be allocated locally while benefits are distributed across the collective.  Our lab has done ample groundwork on this system in charactering the proteins that are socially transferred between individuals, where they are produced, when and by whom.

This project has two parts. One will focus on tracking protein flow between individuals using stable-isotope proteomics and quantitative feeding measures. The second will quantify the metabolic costs of production for the producers and the longevity benefits for receivers using RNAi, artificial diets, and measurements of physiology, oxidative stress, and metabolic rate.  Disentangling metabolic division of labour in ant colonies, where we can monitor exchanges easily, will hopefully allow us to better understand how some of our tissues lighten the load of others and how to better extend life- and health-span.

Negroni & LeBoeuf. Metabolic division of labor in social insects. 2023 COIS https://doi.org/10.1016/j.cois.2023.101085

Hakala SM, Meurville MP, Stumpe M, LeBoeuf AC. 2021. Biomarkers in a socially exchanged fluid reflect colony maturity, behavior, and distributed metabolism. Elife 10. doi:10.7554/eLife.74005

Kramer BH, Nehring V, Buttstedt A, Heinze J, Korb J, Libbrecht R, Meusemann K, Paxton RJ, Séguret A, Schaub F and Bernadou A. (2021) Oxidative stress and senescence in social insects: a significant but inconsistent link? Philosophical Transactions of the Royal Society B, 376(1823), 20190732.