Fig. 1 . The generation of Syne-1 and Syne-2 KASH-domain-deletion mice. (A,B) Schematic representation of the knockout strategies for Syne-1 and Syne-2. Exons are labeled and coding regions are indicated by black boxes. In the targeting vector, the last exon of Syne-1 (the last two exons of Syne-2) was replaced by a neomycin-resistance expression cassette (neo). A HSV-TK cassette was linked to the 5' end (3' end for Syne-2) for negative selection. Restriction enzyme sites: A, AvrII; B, BamHI; E, EcoRI; H, HindIII. (C,D) Southern-blot analyses of genomic DNA from wild-type (+/+), heterozygous (+/-) and homozygous-knockout (-/-) mice. Probes used are indicated in Fig. 1A,B. (C) For Syne-1 analysis, genomic DNA samples were digested by BamHI, which yielded 3.8 kb (wild-type allele) and 5.2 kb (mutant allele) bands (notice that a 4.1 kb band caused by BamHI digestion is visible in all lanes). (D) For Syne-2, SpeI-digested genomic DNA yielded 5.5 kb (wild-type allele) and 2.6 kb (mutant allele) bands. (E-H) Frozen sections of skeletal muscle were stained with anti-Syne-1 (green in E and F) or anti-Syne-2 (green in G and H), and DAPI (blue in all panels). Syne-1 and Syne-2 signals are visible on the nuclear envelope of samples from the control, but not the homozygous-knockout, mice. Scale bar, 25 µm in F for E,F; 10 µm in H for G,H.