The intellectual disability gene Kirrel3 regulates target-specific mossy fiber synapse development in the hippocampus
- University of Utah School of Medicine, United States
- Columbia University, United States
- University of California, San Diego, United States
- F. Hoffmann-La Roche, Switzerland
Figures
Figure 1 with 2 supplements
Kirrel3 is a synaptic molecule that mediates homophilic, trans-cellular adhesion.
(A) Synaptosomes from mouse hippocampi from P9, P21, and adult (P55) were immunoblotted for indicated proteins. lys; lysate. syn; synaptosome. 2 μg protein per lane. (B, C) 14 days in vitro (DIV) …
Figure 1—figure supplement 1
Kirrel1 and 2 are not expressed in the hippocampus.
(A, B) In situ hybridizations for Kirrel1 and Kirrel2 mRNA indicate little to no hippocampal expression. This is in agreement with the Allen Brain Atlas. A, B are tiled images.
Figure 1—figure supplement 2
Kirrel3 undergoes homophilic binding in cells.
(A) HEK293 cells were co-transfected with GFP (cyan) and full-length FLAG-tagged Kirrel cDNAs. Cells were then live labeled with soluble Fc constructs (red). This shows the Kirrel3 extracellular …
Figure 2 with 2 supplements
Hippocampal DG and GABA neurons express Kirrel3.
(A–D) In situ hybridizations for Kirrel3 mRNA on adult P60–P70 hippocampal sections from WT (A–C) and KO (D) mice. A negative control sense probe on WT tissue is shown in C. Red arrows in boxed …
Figure 2—figure supplement 1
Kirrel3 is not expressed by CA3 neurons.
(A) In situ hybridization for Kirrel3 mRNA at P14 shows the same expression pattern as the adult brain shown in Figure 2A. (B) Western blot of hippocampal lysates from adult Kirrel3 wild-type (WT), …
Figure 2—figure supplement 2
Kirrel3 is expressed by mainly calbindin-positive GABA neurons.
(A) Diagram indicating hippocampal region imaged and analyzed is represented inside the blue line. (B) Interneuron analysis of animals heterozygous for Kirrel3 shows little difference from knockout …
Figure 3 with 1 supplement
Kirrel3 regulates MF synapse form and function during development.
(A) MF synapse diagram. TE; thorny excrescence. (B, E) DiI-labeled MF synapses from P14 Kirrel3 WT and KO mice. (C, F) 3D renderings of synapses in (B, E). (D, G) Tracings of representative …
Figure 3—figure supplement 1
Kirrel3 is required for normal development of MF filopodia.
(A, B) Histograms for the number (A) and length (B) of MF filopodia in each genotype. This is the same P14 data plotted in main Figure 3H–K but here the entire range of values for all data is shown.
Figure 4 with 1 supplement
Kirrel3 regulates the activity of CA3 neurons during development.
(A) Evoked responses at −70 and 0 mV of a CA3 neuron after stimulation of the MF pathway in Kirrel3 WT and KO mice. Lower traces show responses of the same cells after perfusion of 0.5 μm DCG-IV. (B)…
Figure 4—figure supplement 1
Spontaneous mEPSC activity of CA3 and DG neurons is normal in the absence of Kirrel3.
(A, B) Graphs depicting time spent in motion (gray) and stationary (orange) of P14 (A) and adult P60–P75 (B) Kirrel3 WT and KO mice during cFos environmental stimulation. No significant differences …
