Second, the p150 subunit was consistently precipitated by antibodies against either Syne-1 or Syne-2 from the E17

Second, the p150 subunit was consistently precipitated by antibodies against either Syne-1 or Syne-2 from the E17.5 brain lysates (Figure 8E). UNC-84 (Malone et al., 1999), are conserved SUN family proteins that contain transmembrane domains spanning the inner nuclear membrane and a C-terminal SUN domain localizing to the lumen of the NE (Haque et al., 2006; Hodzic et al., 2004; Padmakumar et al., 2005). The N-termini of SUN proteins have been shown to be in the nucleoplasm and to interact with nuclear lamins (Crisp et al., 2006; Fridkin et al., 2004; Haque et al., 2006; Mejat et al., 2009). Mammalian Syne-1/Nesprin-1 and Syne-2/Nesprin-2 proteins belong to a family of giant KASH proteins that are conserved in the worm and fly (Starr and Fischer, 2005; Wilhelmsen et al., 2006). PTC-209 HBr The KASH proteins, which contain conserved 60-residue KASH (Klarsicht/ANC-1/Syne Homology) domains at the C-termini (Starr and Han, 2002), have been shown to be recruited to the PTC-209 HBr outer NE through interactions between the KASH domains and SUN domains in the lumen of NE (Crisp et al., 2006; Malone et al., 2003; McGee et al., 2006; Padmakumar et al., 2005; Starr and Han, 2002; Starr et al., 2001). The roles of SUN and KASH proteins and their functional interactions during nuclear positioning were first uncovered by genetic studies in non-mammalian animal models. In and Zebrafish retina, KASH and SUN proteins play critical roles in nuclear movement (Del Bene et al., 2008; Kracklauer et al., 2007; Mosley-Bishop PTC-209 HBr et al., 1999; Tsujikawa et al., 2007). We and others have previously shown that the KASH protein Syne-1/Nesprin-1 and Lamin A/C are essential for the anchorage of synaptic and non-synaptic nuclei of skeletal muscle cells in mice (Grady et al., 2005; Mejat et al., 2009; Puckelwartz et al., 2008; Puckelwartz et al., 2009; Zhang et al., 2007) and that SUN1 is essential for gametogenesis (Chi et al., 2009; Ding et al., 2007). We have also determined that SUN1 and SUN2 play critical and redundant roles in recruiting Syne-1 to the Rabbit Polyclonal to CHST10 NE and in anchoring myonuclei in mice (Lei et al., 2009). However, the neonatal lethality of double KASH deletion (DKD or double knockout mice (DKO or DKD and DKO mutants and uncovered the critical functions of these proteins in nucleokinesis and INM during mammalian brain development. Our results indicate that the SUN-KASH complexes mediate the coupling between the nucleus and the centrosome, and provide anchors in the NE for cytoplasmic dynein/dynactin during neuronal migration. Results Loss of both SUN1 and SUN2 Lead to Severe Laminary Defects in Mouse Brain DKO (DKO embryo indicated severe defects that include malformed cortices, enlarged lateral ventricles and a smaller corpus callosum (Figure 1B; data not shown). Multiple brain regions of the DKO pups displayed severe laminary defects, including loss of the mitral cell layer in the olfactory bulb, loss of the pyramidal cell layer in the hippocampus, loss of the Purkinje cell layer in the cerebellum, and widespread defects in the midbrain and hindbrain (Figure 1C-H). Open in a separate window Figure 1 Brains of DKO embryos display severe laminary defects and inverted layers in multiple brain regions(A-A) Dorsal (A) and ventral (A) views of E18.5 brains. The brains of DKO embryos were significantly smaller than that of their littermates. (B-B) Coronal sections of E18.5 brains at anterior commissure (ac) stained with H&E. Compared to the control, the DKO brain displayed smaller size, significantly enlarged lateral ventricles (asterisk) and abnormal cortical structures (c). cc, corpus callosum. Bar, 1000m. (C-H) Coronal sections of E18.5 brains stained with H&E, showing defects in various regions of DKO brains compared to their PTC-209 HBr littermates. (C) Mitral cell layer was missing in olfactory bulb in the DKO brain (red arrow). (D) Neocortex of the DKO embryo.