Establishment of polarity, which involves orientation and relocation of the cell nucleus, is essential for proliferation and differentiation of a variety of cells including neurons, epithelial cells and myocytes. Current view pictures both actin- and microtubule-mediated nuclear positioning are required for this process. Although cytoskeleton drives different cellular functions, questions remain concerning the orchestration of nuclear positioning or migration relative to other organelles within the cell. The SUN-domain proteins are components of the LINC complex that reside with the inner nuclear membrane. Depletion of the SUN-domain proteins is associated with tissue-specific developmental defects. Here we created Sun1 and Sun2 knockout mice and found both genes are important for the development of cerebellum and hippocampus. More than 70% of Purkinje cells in the Sun1–/– Sun2+/– cerebellum fail to present at the surface of the internal granule layer (IGL). In addition, granule neurons in the Sun1–/– hippocampus are less efficient for retrograde nuclear migration. These results input the current understanding of the SUN-domain proteins for postnatal brain development.
