A, B, Primary cortical neurons transfected with cyt-Fluc-EGFP (A) or nuc-Fluc-EGFP (B) (green), in combination with nuc-mHTT (upper rows) or cyt-mHTT (lower rows) (magenta). Cells were fixed at DIV 3+2 and stained for the neuronal marker MAP2 (grey). Nuclei were labeled with DAPI (blue). Arrowheads point to Fluc-EGFP foci. Dashed lines mark the nuclei. Schemes on the right summarize the cellular distribution of the respective Fluc-EGFP (green) and mHTT (magenta) proteins. Corresponding cultures transfected with control HTT are shown in Appendix Fig. S3A. 