Supplementary Material for: Expression analyses of C-terminal-binding protein 1 (CtBP1) during mouse brain development

Introduction: CtBP1 (C-terminal-binding protein 1) is a multi-functional protein with well-established roles as a transcriptional co-repressor in the nucleus and a regulator of membrane fission in the cytoplasm. Although CtBP1 gene abnormalities have been reported to cause neurodevelopmental disorders, the physiological role and expression profile of CtBP1 remains to be elucidated. Methods: In this study, we used biochemical, immunohistochemical and immunofluorescence methods to analyze the expression of CtBP1 during mouse brain development. Results: Western blotting analyses revealed that CtBP1 appeared to be expressed mainly in the central nervous system throughout the developmental process. In immunohistochemical analyses, region-specific nuclear as well as weak cytoplasmic distribution of CtBP1 was observed in telencephalon at embryonic day (E)15 and E17. It is of note that CtBP1 was barely detected in axons, but observed in the nucleus of oligodendrocytes in the white matter at E17. As to cerebellum at postnatal day 30, CtBP1 appeared to be expressed in the nucleus and cytoplasm of Purkinje cells, the nucleus of granule cells and cells in the molecular layer (ML), and the ML per se where granule cell axons and Purkinje cell dendrites are enriched. In addition, CtBP1 was detected in the cerebellar nuclei. Conclusion: The obtained results suggest involvement of CtBP1 in brain function.