Scale bar, 50 m. On the other hand, MANDYS141 (against R14), MANDRA13 (against the C-terminal domain) and MANDRA14 (against the C-terminal domain) mainly worked in western blot but not immunostaining (except for MANDRA14 which yielded a weak positive signal in the mouse heart) (Figure Ginsenoside F2 5, Table 1). staining and western blot. For comparison, we also included striated muscles from normal BL10 and dystrophin-null mdx mice. Our analysis revealed distinctive species, tissue and assay-dependent recognition patterns of different antibodies. Importantly, we identified 15 antibodies that can consistently detect full-length canine dystrophin in both immunostaining and western blot. Our results will serve as an important reference for studying DMD in the canine model. Introduction Duchenne muscular dystrophy (DMD) is an X-linked degenerative muscle disorder. It is caused by frame shift or frame interruption mutations of the dystrophin gene [1]. The 2 2.3 megabase dystrophin gene is one of the largest known genes representing roughly 0.1% of the genome [2]. The dystrophin gene contains 79 exons and it translates into Ginsenoside F2 a 427 kD cytoskeletal protein [3], [4]. Dystrophin is predominantly expressed in skeletal and cardiac muscles [5]. It belongs to the -spectrin/-actinin protein family [6]. Dystrophin has four structurally distinctive domains. The first 240 amino acid residues form the actin-binding N-terminal domain. Next is a long rod-shaped central domain containing 24 spectrin-like repeats and four proline-rich hinges. The third domain is the cysteine-rich domain. The last 420 amino acid residues constitute the C-terminal domain [7]. Dystrophin localizes to the cytoplasmic surface of the sarcolemma in striated muscles [8]. It establishes a mechanical link between the extracellular matrix and the actin cytoskeleton (reviewed in [9], [10]). Dystrophin-specific antibodies have played a pivotal role in the discovery and subsequent characterization of the dystrophin protein [4], [8], [11]. These antibodies FAE have also been used as Ginsenoside F2 a tool for differential diagnosis of various types of muscular dystrophy [12]C[14]. In light of research and clinical needs, Morris and colleagues developed a series of epitope-specific dystrophin monoclonal antibodies (reviewed in [15]). These antibodies recognize unique epitope(s) in different exon(s) and thus can be used to precisely map gene deletion at the protein level [16], [17]. Besides the diagnostic value, these antibodies have also been widely used to study revertant fibers and smaller non-muscle isoforms of dystrophins [18]C[21]. Epitope-specific dystrophin monoclonal antibodies were initially generated to react with human dystrophin [22]. Interestingly, some of these antibodies also cross-reacted with dystrophins in other species. This provides an excellent opportunity for applying human dystrophin antibodies in preclinical animal studies. Dystrophin-deficient dogs are genetically and clinically comparable to human patients. Experimental therapies performed in dystrophic dogs are expected to more accurately predict the outcome of human trials [23]. To better characterize preclinical study in the canine model, we evaluated 65 dystrophin monoclonal antibodies in the heart and skeletal muscle of normal and dystrophic dogs by immunostaining and western blot. Since these antibodies have not been systemically analyzed in mice either, we also included striated muscles from wild type C57Bl/10 (BL10) and dystrophin-deficient mdx mice in the study. Materials and Methods Experimental Animals All animal experiments were approved by the institutional animal care and use committee of the University of Missouri Ginsenoside F2 and were in accordance with NIH guidelines. Experimental dogs were produced in house by artificial insemination using semen from affected golden retriever, Corgi and Labrador dogs [23]C[25]. Diagnosis was made by PCR genotyping using umbilical cord and confirmed by elevated creatine kinase levels [24], [25]. Experimental dog tissues (from two normal and two affected dogs) were obtained at necropsy from adult dogs that were euthanized for other studies [24], [26], [27]. Specifically, the cranial tibialis muscle was used.