Figure 2.

NEGR1 promotes neurite growth and is permissive for axon growth. (A) Co-cultures of primary cortical neurons and NSC-34 cells expressing NEGR1 and/or enhanced green fluorescent protein (EGFP) immunostained by βIII-tubulin/anti-EGFP antibodies after 2 days of co-cultivation. Cell nuclei were stained by DAPI. (B) NEGR1 expressed by NSC-34 cells promotes neurite growth of co-cultured cortical neurons compared to control (EGFP alone). Mean neurite length per neuron is shown (total number of neurites: NEGR1 + EGFP = 469; EGFP alone = 399, pooled from two independent experiments). (C) Images showing co-cultures of NSC-34 cells expressing NEGR1 and/or EGFP which have been added to primary cortical neurons after 5 days in vitro (DIV) and cultivated for further 2 DIV. Cortical axons were immunostained by anti-synaptobrevin 2 (SYB). (D) The SYB/EGFP area ratio, resembling the area occupied by distal axons on EGFP-positive NSC-34 cell bodies is increased by NEGR1 expression (total number of analyzed cells: NEGR1 + EGFP = 48; EGFP alone = 48, pooled from two independent experiments). ***p < 0.001, Mann Whitney U test. Scales: 50 μm (A); 20 μm (C).