Fig. 1

IPMK deletion triggers dynamic changes in synaptotagmin-2 gene and protein expression specifically. a Scatter plot shows five genes found to differ in the hippocampus of naive IPMK^cKO mice relative to control IPMK^WT mice. The x-axis represents differentially expressed genes of IPMK^WT mice and the y-axis is that of IPMK^cKO mice. The cutoffs for 1.5-fold deviation are indicated by blue lines, respectively. Small gray dots represent sequences with no significant changes, green dots sequences differed genes with no significant (P ≥ 0.05). Red dots sequences significantly up- or down-regulated (P < 0.05). n = 3 (IPMK^WT) and 3 (IPMK^cKO) (b-d) Levels of major synaptotagmin isoforms and synaptic genes were measured using hippocampal samples obtained from IPMK^WT and IPMK^cKO mice. b Cluster analysis of differentially-expressed genes. The horizontal axis displays individual samples, while the vertical axis displays the expressed genes by their z-scores. Red = increased, green = decreased. c, d Quantitative real-time PCR analyses were performed. mRNA expression of the Ipmk and Syt2 were measured (c). Levels of synaptotagmin isoforms Syt1, Syt3, Syt8, Syt11, Syt13, and other synaptic components, Syp, Syngr, Syn1 were measured (d). In all bar graphs, amounts of mRNA were normalized to those from hippocampus of IPMK^WT. n = 3 (IPMK^WT) and 4 (IPMK^cKO) (Student’s t-test; NS, P ≥ 0.05; **P < 0.01; ***P < 0.001) (e) Representative Western blots of IPMK, Syt2, and GAPDH proteins in each mouse hippocampus, amygdala, and cerebellum were presented. f All intensities of Western blot bands were quantified using ImageJ software. GAPDH was used as the loading control for quantification. n = 3 (IPMK^WT) and 4 (IPMK^cKO) (Student’s t-test; NS, P ≥ 0.05; **P < 0.01) (g-j) Immunostaining of hippocampal sections from CA3 (g), CA1 (h), and DG (i, j) of IPMK^WT and IPMK^cKO mice. Top, representative confocal images were stained by Parvalbumin (red), Syt2 (green), and DAPI (blue). Scale bars, 100 μm. PV positive neurons are indicated by arrowheads. Bottom, Levels of PV, Syt2, and DAPI were quantified. Signals from dashed areas were measured by using using ImageJ software. n = 5 (IPMK^WT) and 5 (IPMK^cKO) (Student’s t-test; NS, P ≥ 0.05; ***P < 0.001) In all experiments, IPMK^WT littermates served as controls for IPMK^cKO mice. HIP, hippocampus; AMG, amygdala; CB, cerebellum. Data are presented as the mean ± SE