B6.129S1(Cg)-Lama2^tm1Eeng/J

Stock number: 013786
Product name: dy^W
Strain synonyms: dyw
Research areas: Developmental Biology Research, Mouse/Human Gene Homologs, Neurobiology Research

Description

The dy^W (dyw) knock-in/knockout allele was designed to both abolish laminin alpha 2 (Lama2; merosin) expression and direct lacZ expression by the endogenous Lama2 promoter/enhancer elements. Merosin is normally expressed in striated muscle, peripheral and central nervous systems, thymus, thyroid, intestine, and testis. These dy^W mice may be useful for studying merosin-deficient congenital muscular dystrophy and other muscular dystrophies.

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Detailed description

A targeting vector was designed to insert a β-galactosidase (lacZ) gene and a neomycin (neo) resistance cassette downstream of the start codon of the laminin, alpha 2 (Lama2) gene, abolishing gene function. Heterozygous dy^W mice are viable, fertile and normal in size. Homozygous mice exhibit growth retardation and most die between 8 and 14 weeks of age [Moll et al. Nature September 2001 and Willmann et al. J Neuromuscul Dis. 2017]. Laminin2 (merosin) is normally expressed in striated muscle, peripheral and central nervous systems, thymus, thyroid, intestine, and testis and has been associated with merosin-deficient congenital muscular dystrophy (MCMD). Homozygous dy^W mice are passive, small, and emaciated, and demonstrate partial hindleg lameness and clasping. Their muscles contain necrotic fibers with occasional areas of regeneration, and they exhibit pronounced fibrosis and increased creatine kinase (CK) activity. When heterozygous dy^W mice are bred with transgenic mice expressing the mouse muscle creatine kinase (Ckm or Mck) promoter driving the expression of human LAMA2 gene, the MCMD phenotype was rescued. These transgenic dy^W mice still become increasingly paralyzed with age and develop hindlimb contractures similar to nontransgenic dy^W mice. These dy^W mutant mice may be useful for studying merosin deficiency in MCMD and other muscular dystrophies.

Development

A targeting vector was designed to insert a β-galactosidase (lacZ) and neomycin (neo) resistance cassette downstream of the start codon of the laminin, alpha 2 (Lama2) gene. The construct was electroporated into 129S1/Sv-Oca2⁺ Tyr⁺ Kitl⁺-derived CJ7 embryonic stem (ES) cells. Correctly targeted ES cells were injected into C57BL/6J blastocysts and the resulting chimeric males were bred to Black Swiss females to generate the mutant colony. These mutant mice were then backcrossed to C57BL/6 for at least four generations to produce a colony of dy^W mice. Upon arrival at The Jackson Laboratory, mice were bred to C57BL/6J inbred mice (Stock No. 000664) for at least one generation to establish the colony. A high-density SNP (single nucleotide polymorphism) panel analysis was performed on the rederived living colony at The Jackson Laboratory Repository. This revealed the mice were ~90% C57BL/6 allele-type. After this, mice were additionally backcrossed to C57BL/6J inbred mice using a marker-assisted speed congenic approach to complete this congenic line.

Allele

Symbol: Lama2^tm1Eeng
Name: targeted mutation 1, Eva Engvall
MGI accession ID: MGI:3522319
Generation method: Targeted
Attributes: Reporter; Null/Knockout
Marker symbol: Lama2
Marker name: laminin, alpha 2
Chromosome: 10
Strain of origin: 129S1/Sv-Oca2⁺ Tyr⁺ Kitl⁺
Expressed genes: lacZ,beta-galactosidase,E. coli
Site of expression: expressed in striated muscle, peripheral and central nervous systems, thymus, thyroid, intestine, and testis
Molecular note: Insertion of a lacZ and neomycin resistance cassette 23 bp downstream of the ATG start site disrupts gene transcription.