Skip to main content
. Author manuscript; available in PMC: 2010 Dec 2.
Published in final edited form as: J Neurosci. 2010 Jun 2;30(22):7495–7506. doi: 10.1523/JNEUROSCI.0470-10.2010

Figure 3. Hemi-Synaptogenesis Assay Reveals Distinct Functional Codes for Neurexins Acting on LRRTM2 or Neuroligin-1.

Figure 3

The co-culture assay was modified such that YFP-LRRTM2 or YFP-NLG1(+B) were expressed in hippocampal neurons and these were co-cultured with COS7 cells expressing CFP-tagged neurexins 1β, 2β', 3β', 1α, 2α and 3α (−S4) or (+S4). Co-cultures were immunostained for PSD-95 and Synapsin I.

A. Illustration of the assay showing YFP-LRRTM2 expressed in neurons clustering at contacts with COS7 cells expressing Nrx1β(−S4)-CFP. PSD-95 co-clusters at these sites. The absence of Synapsin I at these clusters indicates the absence of native synapses. Scale bar, 10 µm.

B. Nrx1β(−S4) on COS7 cells clusters both YFP-LRRTM2 and YFP-NLG1 in neurons, Nrx-1β(+S4) clusters only YFP-NLG1, Nrx1α(−S4) clusters only YFP-LRRTM2, and Nrx 1α(+S4) does not cluster either of them. Scale bar, 10 µm.

C. Table showing the clustering code for YFP-LRRTM2 and YFP-NLG1 with all 12 neurexin variants studied. Whereas YFP-LRRTM2 in neurons clustered at contacts with COS7 cells expressing all (−S4) neurexin variants, YFP-NLG1 clustered neurexin β variants and not α variants. (+++++ 90–95% contact sites were positive, +++ 60–80% contact sites were positive, − 0–5% contact sites were positive, n>30 contact sites).