Bergen Stress and Sleep Group, BSSG

Lars Erik Schiro

An evaluation of TimeSTAMP2 knockin mice -For novel drug-dependent epitope-tagging of newly synthesized Arc during long-term potentiation in the dentate gyrus of adult anesthetized mice

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Background: The Arc protein is hypothesized to play a key role in synaptic plasticity, due to its involvement in LTP, LTD and homeostatic scaling. LTP consolidation in the dentate gyrus requires a continuous synthesis of Arc for at least 2-3 hours and a major goal is to elucidate any time-dependent roles of Arc during LTP consolidation.

Method: The novel method TimeSTAMP was developed for the separate detection and tracking of a protein species based on time of synthesis. The method allows drug-dependent tagging and tracking newly synthesized Arc successfully in vitro, and we wish to make it work in vivo as well. A novel TimeSTAMP2 knockin (TS2 KI) mouse line is used for the first time to evaluate the efficacy of the TimeSTAMP2 construct to tag and track newly synthesized Arc in vivo by infusing BILN 2061 directly to the dentate gyrus following highfrequency stimulation (HFS) of the perforant path.

Results: The combined administration of HFS and BILN 2061 is observed to induce dentate gyrus wide Arc expression, and separately tag newly synthesized Arc. The TS2 KI mouse strain’s ability to consolidate LTP over 3 hours could not be confirmed in the homozygous animals.

Conclusion: In vivo TimeSTAMP using the TS2 KI mice shows potential as a tool for visualizing newly synthesized Arc during LTP consolidation. However, further work is needed to optimize the treatment and recording protocols, and to fully validate the drugdependent tagging and function of TimeSTAMP Arc.

The master project was conducted in Bramham Lab , at The Department of Biomedicine, The Faculty of Medicine


Main supervisor: Clive R Bramham

Co-supervisor: Janne Grønli