Neural Plasticity: Characterization of Arc mRNA in Túngara frogs (2009)

Undergraduates: Claire Thomson, Lisa Mangiamele

Faculty Advisor: Sabrina Burmeister
Department: Biology

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This summer I researched the expression of the Arc gene (activity regulated cytoskeleton-associated gene) in tungara frogs (Physalaemus pustulosus). Arc is a gene whose expression is closely linked with neural activity (an immediate-early gene)and the expression of Arc is thought to play a role in the process of neural plasticity. I used P. pustulosus brain tissue that had been previously collected and treated using radioactive in situ hybridization to label the Arc mRNA expressed in the tissue. The subjects were exposed to a 30 minute looped recording of P. pustulosus mating calls. Subjects were sacrificed either before the onset of stimulus (0 min), or at different times following the onset of the stimulus (15m, 30m, 45m, 60m, 90m, 2h, 4h). My results show that the peak expression was 45 minutes after the onset of the sound stimulus. Because there was a statistically significant difference in the levels of mRNA expression in the subjects sacrificed without any sound stimulation vs. those sacrificed 45 minutes after stimulus onset, I concluded that the expression of Arc is activity induced. I then determined the level of Arc expression due to sound exposure in different areas of the brain. The overall implication of these results is that Arc is expressed in response to a mating call stimulus mostly in the forebrain, as opposed to the midbrain. For the last part of my project, I developed the procedure to perform fluorescence in situ hybridization on P. pustulosus tissue.