The hDMD YAC transgene expresses the full-length and functional human dystrophin gene. hDMD transgenic mice are useful for preclinical testing of sequence-specific therapeutics for the treatment of Duchenne muscular dystrophy (DMD). When bred to Dmd-deficient mice, a single copy of the hDMD transgene compensates for the lack of mouse dystrophin and prevents DMD pathology.
Peter A. C. 't Hoen, Leiden University Medical Center (LUMC)
The hDMD transgene is a 2.7 Mbp yeast artificial chromosome (YAC) sequence containing the full-length 2.3 Mbp human dystrophin gene (DMD). This transgene has a single copy integration into mouse chromosome 5. Hemizygous (hDMDTg/0) and homozygous (hDMDTg/Tg) mice are viable and fertile with no reported neuromuscular abnormalities. Transgene expression results in a 427 kDa full-length human dystrophin protein. The added levels of human and mouse dystrophin protein are similar to the levels of the murine protein in wildtype mice. In general, the expression level of the endogenous mouse transcript is lower in homozygotes compared to wildtype mice, indicative of a negative feedback of the human protein on the transcription of the murine gene.
The utrophin/dystrophin double knockout mice (Utrn-/- mdx; see Stock No. 014563) are extremely weak and die between 8-20 weeks of age. If the hDMD transgene is also present, the resulting triple mutant mice (hDMDTg/0 Utrn-/- mdx) exhibit no signs of muscular dystrophy. This demonstrates that one copy of the hDMD transgene (i.e., hDMDTg/0) rescues the lethal dystrophic phenotype of utrophin/dystrophin double knockout mice. Therefore, expression of the hDMD gene normalizes the expression profile of dystrophin-deficient and dystrophin/utrophin-deficient muscles.
The hDMD transgenic mice were created by Dr. Peter A. C. 't Hoen (Leiden University Medical Center). First, a 2.7 Mbp yeast artificial chromosome (YAC) sequence containing the full-length 2.3 Mbp human dystrophin gene (DMD) was obtained. The YAC also contained a hygromycin resistance cassette on one end and a neomycin resistance cassette on the other. Spheroplast fusion of YAC-containing yeast cells with murine (DBA2 x 129OLA)F1-derived embryonic stem (ES) cells resulted in ES cells with single copy integration of the hDMD transgene into mouse chromosome 5. These ES cells were injected into blastocysts that were subsequently implanted into pseudopregnant recipient female mice. Chimeric males were bred to C57BL/6J females to establish founder line "HGEN_0072." The hDMD transgenic mice were backcrossed to C57BL/6J mice (from Charles River Laboratories [Maastricht, The Netherlands]) for a total of at least three generations. In 2014, homozygous males with brown coat color and a light brown belly were sent to The Jackson Laboratory Repository. Upon arrival, sperm was cryopreserved. To generate the living colony, an aliquot of the frozen sperm was used to fertilize oocytes from C57BL/6J inbred females (Stock No. 000664).
|Expressed Gene||DMD, dystrophin, human|
|Site of Expression|
|Allele Name||transgene insertion 72, Peter 't Hoen|
|Allele Type||Transgenic (Inserted expressed sequence, Humanized sequence)|
|Gene Symbol and Name||Tg(DMD)72Thoen, transgene insertion 72, Peter 't Hoen|
|Promoter||DMD, dystrophin, human|
|Expressed Gene||DMD, dystrophin, human|
|Strain of Origin||(DBA/2 x 129P2/OlaHsd)F1|
|Molecular Note||The construct consists of a 2.7 Mbp yeast artificial chromosome (YAC) sequence containing the full-length 2.3 Mbp human dystrophin gene (DMD) and a hygromycin resistance cassette on one end and a neomycin resistance cassette on the other. Spheroplast fusion of YAC-containing yeast cells with murine (DBA2 x 129OLA)F1-derived embryonic stem (ES) cells resulted in ES cells with single copy integration of the transgene into mouse chromosome 5. Analysis by Western blot and human-specific antibody demonstrated the presence of full length protein at the sarcolemma.|
The donating investigator reports homozygous mice are viable and fertile with no obvious functional deficits. When maintaining a live colony, homozygous mice may be bred together. Alternatively, hemizygous mice may be bred together, to wildtype (noncarrier) siblings or to C57BL/6J inbred mice (Stock No. 000664). The donating investigator reports the coat color is brown with a light brown belly with no variations in coat color.
When using the STOCK Tg(DMD)72Thoen/J mouse strain in a publication, please cite the originating article(s) and include JAX stock #018900 in your Materials and Methods section.