SBME Seminar with Dr. Heejun Choi – mRNA Technology Meets Imaging: From Efficient Expression to Spatial Organization of mRNA in Living Cells

Meeting ID: 693 1337 2182

Passcode: 551431

Imaging dynamic processes inside the cell has revolutionized our understanding of how biology organizes itself in space and time. However, these insights have been effectively limited to a small subset of “model” cells due to the lack of a universal expression system that can be easily adopted across diverse cell types, tissues, and physiological states. While mRNA technology has the potential to overcome many of these bottlenecks, it has not been widely utilized for this purpose. In this talk, I will discuss how optimizing mRNA synthesis and nucleotide modifications can bridge this gap. I will introduce mRNAbow, a modular platform utilizing in vitro transcribed mRNA with modified nucleotides to enable robust, low-toxicity protein expression in cell lines, primary cells, tissues, and developmental systems. Imaging-based analysis reveals strong cell-type-dependent differences in how exogenous mRNAs are processed and translated, underscoring the importance of cellular context in selecting optimal nucleotide modifications. Additionally, through imaging single mRNA molecules, I will demonstrate how endogenous mRNAs exhibit spatially organized translation, with membrane protein mRNAs concentrating at specific domains within the endoplasmic reticulum. I will show how interactions between these domains and lysosomes integrate cellular signaling and amino acid availability to control overall membrane and secretory protein output. Together, these findings illustrate how mRNA technology and imaging can be used to uncover fundamental principles of mRNA biology in living cells.

Dr. Heejun Choi’s Biography:

Heejun Choi is a research scientist at the Janelia Research Campus of the Howard Hughes Medical Institute in the laboratory of Dr. Jennifer Lippincott-Schwartz. He received his Ph.D. in Chemistry from the University of Wisconsin–Madison under the supervision of Dr. James Weisshaar. His research integrates mRNA technology, quantitative imaging, and chemical biology to understand how RNA design, cellular organization, and metabolic state influence gene expression in living systems.

Professional or lab links: https://orcid.org/0000-0002-1337-3813