Figure 7.

Mutant FUS and FUS(LC) Domain, but Not Full-Length Wild-Type FUS, Cause Reduced New Protein Synthesis When Expressed in Cultured Neurons

(A) New protein synthesis was detected by puromycylation in axon terminals of cultured Xenopus retinal ganglion neurons (left panel: phase contrast; right panel: anti-puromycin fluorescent images) expressing equivalent quantities of full-length FUS(WT) or various mutant and truncated human FUS proteins. Scale bar, 10 μm.

(B) Under basal conditions, de novo protein synthesis is equivalent in non-injected neurons, and in neurons expressing FUS(WT). However, de novo protein synthesis was significantly reduced in neurons expressing ALS/FTD mutants including: FUS(R522G), FUS(R524S), FUS501, FUS(R495X), and in gelling-prone FUS(LC)(WT), FUS(LC)(S96del), FUS(LC)(G156E), FUS(LC)(P21H), and FUS(LC)(N63S). In good agreement with the in vivo studies in C. elegans, heat shock causes significant reduction of new protein synthesis in neurons expressing mutant FUS, but minimal impact on non-transfected and FUS(WT) expressing neurons (right panel). N.S., not significant; ^∗p < 0.05, ^∗∗p < 0.01, and ^∗∗∗p < 0.001.

Error bars are SEM.