Neuroligin-1 overexpression increases dendritic spine number.

<p>A. Dendritic spine morphology as demonstrated from GFP expression in 21-day-old granule cells expressing GFP only (control) or HA-neuroligin-1 in conjunction with GFP. Scale bar: 5 μm. B. To control for variability between fluorophore expression levels, a subset of 21-day-old live cells was identified by GFP expression, filled with membrane-impermeant dye by patch pipette, and fixed. Images show sections of dendrite taken from 21-day-old control cells and neuroligin-1 overexpressing cells. Scale bar: 5 μm. C. The dentate middle molecular layer of an adult mouse co-injected with separate retroviruses expressing mCherry (control) or neuroligin-1 IRES GFP. The projected image shows a 21-day-old control granule cell (mCherry) next to a GFP-filled cell overexpressing neuroligin-1. Scale bar: 5 μm. D, E. Summary data of spine measurements from infected cells 21 days post-mitosis demonstrating an increase in spine density but no change in spine length. Control neurons were infected with a retrovirus expressing GFP only (data shown ± SEM; control, n = 11 cells; NLG-1, n = 10 cells; ***p<0.005).