Fig 7. Axon markers SMI31 and tau in multi-neuritic neurons.

(A-D) Confocal images of hippocampal neurons co-transfected with control (A₁-D₁), a-SMN (A₂-D₃) or FL-SMN (A₄-D₅) specific siRNAs and the Venus plasmid (green, A₁-A₅ and C₁-C₅), fixed at 3DIV and labeled with the axonal markers SMI31 (blue, B₁-B₅) or tau (red, D₁-D₅). While neurons transfected with control siRNA had a single axon labeled by SMI31(A₁-B₁), in a-SMN and FL-SMN-silenced neurons displaying multi-neuritic morphology, SMI31or tau axonal staining was mainly in soma (B₅, D₂, D₄) or variably localized in two or more neuritic processes (B₂-B₄, D₃, D₅). (E) Quantification of axon labeling in individual multi-neuritic neurons. Stacked histograms showing SMI31 distribution in a-SMN and FL-SMN silenced neurons with multi-neuritic morphology. Data are presented as mean ± SEM. At least 70 cells from three different experiments were analyzed. Percent ratio of axonal markers distribution (multineurites/ only soma/axonal labeling) was compared by means of chi-square test (** p<0.01) between the two experimental conditions (a-SMN or FL-SMN siRNA). Scale bar: 10 μm.