| First Author | Marlow SA | Year | 1995 |
| Journal | Mouse Genome | Volume | 93 |
| Issue | 2 | Pages | 436-8 |
| Mgi Jnum | J:26241 | Mgi Id | MGI:73920 |
| Citation | Marlow SA, et al. (1995) MyoD1 alleles allow distinction between M. m. musculus and M. m. domesticus subspecies. Mouse Genome 93(2):436-8 |
| abstractText | Full text of Mouse Genome contribution: MyoD1 alleles allow distinction between M. m. musculus and M. m. domesticus subspecies. Marlow, S.A., Kay, P.H. and Papadimitriou, J.M. Molecular Pathology Laboratory, Department of Pathology, University of Western Australia, Nedlands, Western Australia, 6009, Australia. Telephone: (61-9)346 2993, E-mail: peterkay@uniwa.uwa.edu.au, FAX: (61-9)346 2891. MyoD1 encodes one of the members of the family of DNA binding proteins which plays a major role in skeletal muscle formation (1). Previously we have shown that MyoD1 is polymorphic among inbred laboratory mice (2). An unusual form of MyoD1, which was presumed to be exclusive to SJL/J mice, was found to be associated with an increased ability to regenerate crush injured skeletal muscle (2). Restriction mapping suggested that the unusual form of MyoD1 found in SJL/J mice may haveresulted from a double recombinant event involving apparent founder forms of MyoD1. The upstream flanking region in SJL/J mice also exhibited a unique arrangement of potential enhancer motifs recognized by variation in the size of fragments following PvuII digestion (2). SJL/J mice have previously been classified as belonging to the Mus musculus (M. m.) domesticus subspecies (3). In order to extend studies on the unusual form of Myo-D1, mice bearing the SJL/J allele were sought in wild mice belonging to the M. m. domesticus subspecies in Western Australia. The SJL/J type of MyoD1 allele could not be found in the M. m. domesticus wild mouse gene pool (4). Therefore, DNA was examined from wild mouse derived lines originating from various geographical locations world-wide and representing various subspecies of mouse to determine the origin of the unusual MyoD1 allele. The twenty one mice studied (see Table I) were obtained from The Institut des Sciences dekÕEvolution in Montpellier, France. These mice have been classified as M. m. musculus, M. m. domesticus or otherwise on the basis of biochemical and genetic markers (5, 6). Mice belonging to the classical inbred strains SJL/J, BALB/c and C3H were obtained from the Animal Resources Centre at Murdoch University in Perth, Western Australia and used as markers for the three previously identified MyoD1 alleles (2). Genomic DNA from all mice was digested with Taq1, Southern (7) blotted and hybridized to the murine MyoD1 1.8-kb cDNA probe (1). The results are summarised in Table 1. Table 1. MyoD1 allelic typing of mouse strains. The presence or absence of Taq1 and PvuII fragments are indicated by the symbols + or - respectively. Mouse species: M. m. domesticus; Enzyme: Taq1; Probe: MyoD1 1.8 -kb; Fragment sizes (kb): 4.1: +; 2.3: -; 1.8: -; 0.6: +; Enzyme: PvuII; Probe: MyoD1 5'; Fragment sizes (kb): 3.4: +; 2.7: -; Strains: BALB/c, DGA. Mouse species: M. m. domesticus; Enzyme: Taq1; Probe: MyoD1 1.8 -kb; Fragment sizes (kb): 4.1: -; 2.3: +; 1.8: +; 0.6: -; Enzyme: PvuII; Probe: MyoD1 5'; Fragment sizes (kb): 3.4: +; 2.7: -; Strains: C3H, BIK, BFM, BNC, DBV, DJO, DOT, DMZ, DDO. Mouse species: M. spretus; Enzyme: Taq1; Probe: MyoD1 1.8 -kb; Fragment sizes (kb): 4.1: +; 2.3: -; 1.8: -; 0.6: +; Enzyme: PvuII; Probe: MyoD1 5'; Fragment sizes (kb): 3.4: -; 2.7: +; Strains: STF. Mouse species: M. m. musculus; Enzyme: Taq1; Probe: MyoD1 1.8 -kb; Fragment sizes (kb): 4.1: -; 2.3: +; 1.8: -; 0.6: +; Enzyme: PvuII; Probe: MyoD1 5'; Fragment sizes (kb): 3.4: -; 2.7: +; Strains: SJL/J, MBP, MGL, MBK, MDB, MAM, MGT, MBS, MGA. Mouse species: M. m. bactrianus; Enzyme: Taq1; Probe: MyoD1 1.8 -kb; Fragment sizes (kb): 4.1: -; 2.3: +; 1.8: -; 0.6: +; Enzyme: PvuII; Probe: MyoD1 5'; Fragment sizes (kb): 3.4: -; 2.7: +; Strains: BIR. Mouse species: M. m. castaneus; Enzyme: Taq1; Probe: MyoD1 1.8 -kb; Fragment sizes (kb): 4.1: -; 2.3: +; 1.8: -; 0.6: +; Enzyme: PvuII; Probe: MyoD1 5'; Fragment sizes (kb): 3.4: -; 2.7: +; Strains: CTA. Mouse species: M. m. molossinus; Enzyme: Taq1; Probe: MyoD1 1.8 -kb; Fragment sizes (kb): 4.1: -; 2.3: +; 1.8: -; 0.6: +; Enzyme: PvuII; Probe: MyoD1 5'; Fragment sizes (kb): 3.4: -; 2.7: +; Strains: MOL. DNA from the 8 different and unrelated members of the M. m. musculus group, as well as DNA from examples of the subspecies M. m. bactrianus, M. m. molossinus and M. m. castaneus, exhibited the same banding pattern as SJL/J mice with fragments of 2.3-kb and 0.6-kb (Fig. 1B). By contrast, DNA from 8 examples of the M. m. domesticus group, as shown in Fig. 1A, had fragments of 2.3-kb and 1.8-kb as found in C3H, CBA and DBA/I mice (2). DNA from one example of M. m. domesticus, DGA, as well as DNA from an example of M. spretus, STF, had fragments of 4.1-kb and 0.6-kb which are similar in size to those found in BALB/c mice (2). These data indicate that the SJL/J type of MyoD1 allele is not unique but common to all subspecies of M. musculus except M m. domesticus. Fig. 1. (Legend). Illustration of fragment sizes hybridising with the MyoD1 1.8-kb probe following digestion of genomic DNA with Taq1. A. Lanes 1-13 contain DNA samples from mouse strains STF, DDO, DMZ, DOT, DJO, DGA, BIK, BFM, BNC, DBV, C3H, BALB/c and SJL/J respectively. B. Lanes 1-15 contain DNA samples from mouse strains STF, CTA, BIR, MOL, MGA, MBS, MGT, MAM, MGL, MPB, MDB, MBK, C3H, BALB/c and SJL/J respectively. Methods: Genomic DNA was extracted from spleen tissue using the standard phenol/ chloroform method (11) and digested withTaq1 or PvuII (Promega, Madison, WI, USA) in compliance with the manufacturer's instructions. DNA fragments were subjected to blot analysis (7) and hybridised with the MyoD1 1.8-kb or the MyoDl 5' 1.0-kb probe. The MyoD1 1.8-kb probe consisted of a full length cDNA insert excised from the clone pVZCIIalpha with EcoRI (1). The MyoD1 5' probe consisted of approximately 1.0-kb of genomic DNA insert excised from the clone pMDG KA with KpnI + ApaI. This probe contains the genomic region from approximately -6 to -7-kb upstream from the beginning of the MyoD1 coding region. Autoradiography was carried out over a two day exposure. To confirm this observation, structural variation of the 5' sequences flanking MyoD1 was also assessed. PvuII digested genomic DNA from the various groups was hybridised with a 1.0-kb genomic DNA probe comprising the region located at 6 to 7-kb upstream from MyoD1. As shown in Fig. 2A, DNA from all M. m. domesticus lines examined exhibited the 3.4-kb fragment found in BALB/c and most other laboratory mice. By contrast, DNA from all M. m. musculus lines possessed the same 2.7-kb fragment found in SJL/J mice (Fig. 2B). Examples of the other groups including M. m. castaneus, M. m. molossinus and M. m. bactrianus as well as Mus spretus also had the same 2.7-kb fragment common to M. m. musculus lines and SJL/J mice. M. spretus, therefore, has structural features of MyoD1 common to each of the two major subspecies. Fig. 2. (Legend). Comparison of fragment sizes hybridising with the MyoD1 5' probe following digestion of genomic DNA with PvuII. A. Lanes 1-13 contain DNA from mouse strains SJL/J, BALB/c, C3H, BlK, BFM, BNC, DBV, DJO, DOT, DMZ, DDO, DGA and STF respectively. B. Lanes 1-15 contain DNA from mouse strains SJL/J, BALB/c, C3H, MPB, MGL, MBK, MDB, MAM, MGT, MBS, MGA, BIR, MOL, CTA and STF respectively. Results of these studies indicate that unlike most other polymorphic markers (8), different allelic forms of MyoD1 allow distinction between the M. m. domesticus and M. m. musculus wild mouse gene pools. Thus on the basis of MyoD1 allotyping most laboratory mice may be classified as belonging to the M. m. domesticus subspecies whilst SJL/J mice appear to have been derived from M. m. musculus. Classification of laboratory mice using MyoD1 allotyping contrasts with Y-chromosome markers (3), however it is consistent with the classification concluded by most other methods (5, 9, 10). Finally, since increased efficiency of regeneration of skeletal muscle is associated with the SJL/J type of MyoD1 allele in laboratory mice (Kay et al. 1993), it will be of interest to determine whether the efficiency of skeletal muscle regrowth also differs between the two major subspecies of wild mouse. ACKNOWLEDGEMENTS We thank Dr S. Tapscott for provision of the MyoD1 cDNA and 5' genomic probes. 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