Fig. 4

Nlgn1 expressed at postsynaptic terminals specifically recruits beta-Nrxn1, but not alpha-Nrxn1, at the presynapse. A. Panels showing the presynaptic recruitment of alpha- and beta-Nrxn1 splice isoforms induced by postsynaptic Nlgn1, as indicated. Nlgn1 was expressed in sparse neurons from cortical cultures expressing alpha- or beta-Nrxn1 isoforms by lentiviral transduction. As a control, Nlgn1 was expressed in non-transduced cultures. Expression of Nlgn1 and Nrxn1 isoforms was analysed with VSV and Flag antibodies, respectively. Synapses were identified with a synapsin antibody. B. Graphs showing the quantification of the Nrxn1 signal (left) and synapsin-positive area (right) at presynaptic terminals induced by postsynaptic Nlgn1. Scale bar, 10 μm