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C9orf72 Poly(Pr) Mediated Neurodegeneration Is Associated With Nucleolar Stress, M. E. Cicardi, J. H. Hallgren, D. Mawrie, K. Krishnamurthy, S. S. Markandaiah, A. T. Nelson, V. Kankate, E. N. Anderson, P. Pasinelli, U. B. Pandey, C. M. Eischen, D. Trotti

Farber Institute for Neuroscience Faculty Papers

The ALS/FTD-linked intronic hexanucleotide repeat expansion in the C9orf72 gene is aberrantly translated in the sense and antisense directions into dipeptide repeat proteins, among which poly proline-arginine (PR) displays the most aggressive neurotoxicity in-vitro and in-vivo. PR partitions to the nucleus when heterologously expressed in neurons and other cell types. We show that by lessening the nuclear accumulation of PR, we can drastically reduce its neurotoxicity. PR strongly accumulates in the nucleolus, a nuclear structure critical in regulating the cell stress response. We determined that, in neurons, PR caused nucleolar stress and increased levels of the transcription factor p53. …