Figure 7. Deletion of Shisa7 specifically affects contextual fear memory.

(a,c) Experimental set-up of measuring contextual fear conditioning memory (a,c), in which mice received a foot shock (US) in a specific environment (CS), and freezing was assessed upon re-exposure to the CS 2 hr, or 24 hr later to measure short term and long term contextual fear memory, respectively. (b,d) For Shisa7 KO mice, both a short term fear memory deficit (n_WT = 8, n_KO = 7; unpaired t-test, p<0.001; (b), as well as a long term fear memory deficit (n_WT = 9 n_KO = 10; Mann-Whitney U-test, p=0.001; (d) were observed. (e) Experimental set-up of measuring auditory fear conditioning memory, in which a 30 s tone co-terminated with a foot shock and memory was tested 24 hr after conditioning in a novel environment to measure generalization of fear (pre-tone), and the auditory fear memory in response to cue presentation (tone). (f) Auditory fear memory was not affected by genotype (n_WT = 13, n_KO = 12; ANOVA, F(1,23)=0.733 p=0.401). Individual data is shown in Figure 7—figure supplement 1.

Figure 7—figure supplement 1. Deletion of Shisa7 specifically affects contextual fear memory.

In addition to the set-ups (a,c,e) and average freezing data of Figure 7, the individual data are shown for short term fear memory (n_WT = 8, n_KO = 7; b), long term fear memory (n_WT = 9 n_KO = 10; d), as well as long-term auditory fear memory (n_WT = 13, n_KO = 12).

Figure 7—figure supplement 2. Shisa7 KO mice display no abnormalities in shock sensation, locomotor activity or anxiety-related behavior.

(a) Mean velocity in the 3 minutes prior to shock (left), or during the 2 s 0.7 mA shock (right) was not different between Shisa7 KO (n = 10) and WT littermates (n = 9), indicating no effect on basal locomotor activity (unpaired t-test p=0.245) or the perception of the shock (unpaired t-test p=0.573). (b–d) A set of anxiety tests (open field, elevated plus maze (EPM), and dark-light box (DL-box)) was carried out sequentially in a batch of Shisa7 KO (n = 8) and WT littermates (n = 8) (cf. Supplementary Figure 2). (b) Open field exploratory behavior (total distance moved) or the anxiety-related component (time spent in the center) was not different between genotypes (MWU tests, p=0.798; p=0.878, respectively). (c) EPM anxiety parameters were similar for Shisa7 and WT mice for the percentage of visits to the open arms (MWU test, p=0.105), and time spent in the open arms (MWU test, p=0.234). Only in this test, one Shisa7 KO mouse was identified as outlier, and when removed this made the difference even smaller (p=0.189, p=0.397). (d) None of the anxiety-motivational parameters measured in the DL-box showed a genotype difference, with time spent in the light compartment, visits to the light compartment and latency to visit to the light compartment being non-significant (MWU tests, p=1.000; p=1.000; p=0.121, respectively). Only for latency, one WT mouse was identified as outlier, and when removed this made the difference even smaller (p=0.209).