Drosophila Neuroligin3 Regulates Neuromuscular Junction Development and Synaptic Differentiation [Developmental Biology]

September 16th, 2014 by Xing, G., Gan, G., Chen, D., Sun, M., Yi, J., Lv, H., Han, J., Xie, W.

Neuroligins (Nlgs) are a family of cell adhesion molecules thought to be important for synapse maturation and function. Mammalian studies have shown that different Nlgs have different roles in synaptic maturation and function. And in Drosophila melanogaster, Drosophila Neuroligin1 (DNlg1), DNlg2, and DNlg4's roles have been examined. However, the roles of DNlg3 in synaptic development and function have not been determined. In this study, we used the Drosophila neuromuscular junctions (NMJs) asa model system to investigate the in vivo role of DNlg3. We showed that DNlg3 was expressed in both CNS and NMJs where it was largely restricted to the postsynaptic site. We generated dnlg3 mutants and showed that these mutants exhibited an increased bouton number and reduced bouton size compared to the wild-type (WT) controls. Consistent with alterations in bouton properties, pre- and postsynaptic differentiations were affected in dnlg3 mutants. This included abnormal synaptic vesicle endocytosis, increased PSD length and reduced GluRIIA recruitment. In addition to impaired synaptic development and differentiation, we found that synaptic transmission was reduced in dnlg3 mutants. Altogether, our data showed that DNlg3 was required for NMJ development, synaptic differentiation and function.