Summary of the breeding schemes.

Adult Nlgn3^y/– mice (2–4 mo old) are submissive to their Nlgn3^y/+ littermates. Littermate groups were composed of (1) Nlgn3^y/+ mice in SGH and (2) Nlgn3^y/+ and Nlgn3^y/– mice in MGH. A, Nlgn3^y/– mice from MGH spent less time vocalizing to a female in estrus compared with Nlgn3^y/+ from MGH. B, Nlgn3^y/– mice from MGH lost more frequently in the tube test against their Nlgn3^y/+ littermates. C, Absence of correlation between rank in the tube and ultrasonic vocalization tests in MGH mice. D, For each group of mice from SGH and MGH, we plotted the rank in the vocalization test for the mice that were dominant in the tube test. All mice from SGH that won in the tube test also vocalized the most, and 5 of 13 mice from MGH (38%) that won in the tube test vocalized the most. For mice from MGH, black dots with gray circles are Nlgn3^y/+ mice, and gray dots with black circles are Nlgn3^y/– mice. Values are represented as mean ± SEM. Statistical significance was tested by two-tailed t test (A) and two-tailed Mann–Whitney test (B and C); *P < 0.05; **P < 0.01.

Decreased competitive behavior in adult (2- to 4-mo-old) Nlgn3^y/– and Nlgn3^y/+ mice from MGH. A, Nlgn3^y/– mice from MGH were defeated more frequently than Nlgn3^y/+ and Nlgn3^{y/ –} mice from SGH when opposed to an unfamiliar submissive male in the tube test. B, Increased urinary testosterone levels in Nlgn3^y/+ mice from SGH. C, Housing conditions did not modify the time Nlgn3^y/+ or Nlgn3^y/– mice spent calling a female in estrus. Regardless of the housing conditions, Nlgn3^y/– mice spent less time calling a female in estrus than Nlgn3^y/+ mice. Note that data from were replotted here to allow comparison. D, Hepatic mRNA expression levels of Cyp2d9 were similar between mice in MGH and SGH. Values are represented as mean ± SEM. Statistical significance was tested by Kruskal–Wallis test and post hoc Tukey’s multiple comparison test (A and B) and one-way ANOVA and post hoc Tukey’s multiple comparison test (C and D). *P < 0.05; **P < 0.01; ***P < 0.001.

Adult (2- to 4-mo-old) Nlgn3^y/– mice modify the social behavior of their littermates. A, Nlgn3^y/+ and Nlgn3^y/– mice from SGH and Nlgn3^y/– mice from MGH showed increased interest in social odors compared with water, whereas this increased interest was absent in Nlgn3^y/+ mice from MGH. Note that Nlgn3^y/+ and Nlgn3^y/– mice from SGH spent more time sniffing the social odor compared with Nlgn3^y/+ and Nlgn3^y/– mice from MGH, respectively. B, Nlgn3^y/+Pvalb^Cre/+ and Nlgn3^y/–Pvalb^Cre/+ mice showed an increased interest for social odors compared with Nlgn3^y/+ and Nlgn3^y/– mice from MGH. C, Western blot analysis shows a ratio of re-expression of 0.7 in the cerebellum, 0.15 in the brainstem, 0.1 in the striatum, 0.1 in the thalamus, and 0.04 in the cortex and no re-expression in the hippocampus. Note that the upper band in the brainstem Nlgn3^y/– sample is most likely unspecific, as it appears in protein samples from Nlgn3^y/– mice. D, Nlgn3^y/– and Nlgn3^y/+ mice from MGH lost more frequently against an unfamiliar submissive mouse compared with Nlgn3^y/–Pvalb^Cre/+ and Nlgn3^y/+Pvalb^Cre/+ mice. No difference in the percentage of wins against an unfamiliar submissive male was found in the tube test between Nlgn3^y/+Pvalb^Cre/+ and Nlgn3^y/–Pvalb^Cre/+ mice. Note that Nlgn3^y/+ and Nlgn3^y/– mice from MGH data are replotted from . The dotted line represents the mean percentage of wins for Nlgn3^y/+ mice from SGH. E, Nlgn3^y/– mice from MGH and Nlgn3^y/–Pvalb^Cre/+ mice spent less time calling a female in estrus than Nlgn3^y/+ mice from MGH and Nlgn3^y/+Pvalb^Cre/+mice, respectively. The dotted line represents the mean time sent calling for Nlgn3^y/+ mice from SGH, replotted from . Values are represented as mean ± SEM. Statistical significance was tested by two-way ANOVA repeated-measures (A), two-way ANOVA (B, D, and E), and post hoc Sidak’s multiple comparison test. *P < 0.05; **P < 0.001; ****P < 0.0001.

In young mice (P21–P28), MGH modifies the interest in social interaction of Nlgn3^y/+ and Nlgn3^y/– but not Nlgn3^–/–mice. A, At P21–P28, Nlgn3^y/+ and Nlgn3^y/– from SGH and Nlgn3^y/+Pvalb^Cre/+ and Nlgn3^y/–Pvalb^Cre/+ mice spent more time in contact with an unfamiliar female than Nlgn3^y/+ and Nlgn3^y/– mice. B, C, No difference in the total distance and the normalized distanced traveled in the center of the OF. D, No difference in the time spent in the open arms of the EPM. E–H, MGH has no significant effect on the time spent in social interaction, the total distance and normalized distance traveled in the center of the OF, and the time spent in the open arm of the EPM of females lacking Nlgn3 (Nlgn3^–/–). Values are represented as mean ± SEM. Statistical significance was tested by two-way ANOVA and post hoc Sidak’s multiple comparison test (A–C). ***P < 0.001.

Increased anxiety in adult (2- to 4-mo-old) Nlgn3^y/– mice from MGH. A, Increased distance traveled in OF in Nlgn3^y/– mice from MGH compared to Nlgn3^y/– mice in SGH and Nlgn3^y/+. B, No change in the average number of beam breaks per hour recorded over 30 h. C, Number of beam breaks per hour over 30 h. D, Increased normalized distance traveled in the center of the OF for Nlgn3^y/– mice in SGH compared with Nlgn3^y/+ mice from SGH and mice from MGH. E, Increased number of marbles buried by mice in MGH compared with mice from SGH. Nlgn3^y/– mice in SGH buried fewer marbles than Nlgn3^y/+ mice in SGH. Values are represented as mean ± SEM. Statistical significance was tested by two-way ANOVA and post hoc Sidak’s multiple comparison test. *P < 0.05; **P < 0.01; ***P < 0.001 (A, B, D, and E).

Adult (2- to 4-mo-old) Nlgn3^–/– mice modify the social behavior of their littermates. We analyzed two littermate groups in which (1) Nlgn3^+/– mice (Nlgn3^+/–_H-WT) were littermates of Nlgn3^+/+ mice or (2) Nlgn3^+/– mice (Nlgn3^+/– _H-KO) were littermates of Nlgn3^–/– mice. A, Nlgn3^+/–_H-KO and Nlgn3^–/– mice spent less time in contact with an unfamiliar female than Nlgn3^+/+ and Nlgn3^+/–_H-WT mice. B, Increased distance traveled by Nlgn3^–/– mice in the OF compared with Nlgn3^+/–_H-WT and Nlgn3^+/–_H-KO mice. C, Increased normalized distance traveled in the center of the OF for Nlgn3^–/– mice. D, No change in the time spent in the open arms of the EPM. Values are represented as mean ± SEM. Statistical significance was tested by one-way ANOVA and post hoc Tukey’s multiple comparison test (A, C, and D) and Kruskal–Wallis and post hoc Dunn’s multiple comparison tests (B). *P < 0.05; **P < 0.001; ***P < 0.001; ***P < 0.0001.