Real-time visualization of mRNA synthesis during memory formation in live mice
Memories are thought to be encoded in populations of neurons called memory trace or engram cells. However, little is known about the dynamics of these cells because of the difficulty in real-time monitoring of them over long periods of time in vivo. To overcome this limitation, we present a genetically-encoded RNA indicator (GERI) mouse for intravital chronic imaging of endogenous Arc mRNA—a popular marker for memory trace cells. We used our GERI to identify Arc-positive neurons in real time without the delay associated with reporter protein expression in conventional approaches. We found that the Arc-positive neuronal populations rapidly turned over within two days in the hippocampal CA1 region, whereas ~4% of neurons in the retrosplenial cortex (RSC) consistently expressed Arc following contextual fear conditioning and repeated memory retrievals. Dual imaging of GERI and a calcium indicator in CA1 of mice navigating a virtual reality environment revealed that only the population of neurons expressing Arc during both encoding and retrieval exhibited relatively high calcium activity in a context-specific manner. This in vivo RNA imaging approach opens the possibility of unraveling the dynamics of the neuronal population underlying various learning and memory processes. 

Seminar Details

Seminar Host

• Prof. Jian-Ping Wang, University of Minnesota 

Seminar Speaker

• Prof. Hye Yoon Park, University of Minnesota

Date and Time

• September 30, 2022

• 11:30am-12:30pm CT

Location
Virtual Via Zoom - Link will be provided upon registration

Dr. Hye Yoon Park is an Associate Professor in the Department of Electrical and Computer Engineering at the University of Minnesota, Twin Cities. She received her B.S. in Physics from Seoul National University and her M.S. and Ph.D. in Applied Physics from Cornell University. For her M.S. degree, she developed microfabrication processes for polymeric microfluidic devices in Prof. Harold G. Craighead’s group. During her Ph.D. research under the guidance of Prof. Lois Pollack and Prof. Watt W. Webb, she developed a laminar flow mixer for kinetic studies of protein and RNA folding on a microsecond time scale. She performed postdoctoral research in the laboratory of Prof. Robert H. Singer at Albert Einstein College of Medicine as an NIH Ruth L. Kirschstein National Research Service Award (NRSA) Postdoctoral fellow. Before joining the University of Minnesota, Dr. Park was an Assistant and Associate Professor at Seoul National University from 2014 to 2022. She received the Howard Hughes Medical Institute-Wellcome Trust International Research Scholar Award in 2017.