Fig. 2.

RNF8 suppresses granule neuron to Purkinje cell neurotransmission in the cerebellum. a Acute sagittal cerebellar slices from P20–25 RNF8 cKO and control mice were subjected to electrophysiological analyses. Evoked excitatory postsynaptic currents (EPSCs) were recorded in Purkinje neurons in response to stimulation of parallel fibers with increasing intensity (30, 40, and 50 μA). Representative current traces (left) and quantification of the amplitude of evoked EPSCs (right) are shown. The amplitude of evoked EPSCs in Purkinje neurons was increased in RNF8 cKO mice compared to control mice (*p < 0.05 at 30 and 40 μA, ***p < 0.005 at 50 μA, ANOVA followed by Fisher’s PLSD post hoc test, n = 14–15 neurons, four mice). b Acute coronal cerebellar slices were prepared as in (a), and parallel fiber axons were stimulated at sites 400 μm away from an extracellular recording electrode. A representative trace of the stimulus-evoked presynaptic waveform before and after the application of tetrodotoxin is shown (left). The stimulus artifact was removed for clarity. On the right, quantification of presynaptic volley amplitude is shown. Conditional knockout of RNF8 had little or no effect on the presynaptic volley amplitude. c, d Acute sagittal cerebellar slices were prepared as in (a) and Purkinje cell miniature EPSCs (mEPSCs) were recorded. Representative traces of mEPSCs from RNF8 cKO and control mice are shown (c, left). Quantification of the mean (c, right) and cumulative distribution (d) of the mEPSC frequency and amplitude are shown. The frequency of mEPSCs was increased in RNF8 cKO mice compared to control mice (*p < 0.05, t test, n = 18–20 neurons, three mice). Conditional knockout of RNF8 had little or no effect on the amplitude of mEPSCs in Purkinje neurons