Complete deletion of all alpha-dystrobrevin isoforms does not reveal new neuromuscular junction phenotype.
The dystrophin glycoprotein complex (DGC) is critical for muscle stability, and mutations in DGC proteins lead to muscular dystrophy. The DGC also contributes to the maturation and maintenance of the neuromuscular junction (NMJ). The gene encoding the DGC protein alpha-dystrobrevin undergoes alternative splicing to produce at least five known isoforms. Isoform-specific antibody staining and reverse transcription PCR in mutant mice with a deletion of exon 3 of the alpha-dystrobrevin gene suggested the existence of a remaining synaptic isoform, which might be compensating for alpha-dystrobrevin function. To test this possibility and to more completely understand the synaptic function of alpha-dystrobrevin, we used a two-step homologous recombination strategy combined with in vivo Cre-mediated excision to generate mice with a large deletion of the alpha-dystrobrevin gene to disrupt all isoforms. However, these mice did not exhibit a more severe NMJ phenotype than that observed in the exon 3-deleted mice. Nonetheless, these mice not only eliminate possible compensation by remaining isoforms of alpha-dystrobrevin, but also offer a conditional allele that could be used to identify tissue-specific and developmental functions of alpha-dystrobrevin. This work also demonstrates a successful strategy to achieve deletion of a large genomic sequence, which can be a valuable tool for functional studies of genes encoding multiple isoforms that span a large genomic region.
Wang
Dongqing
D
Department of Neurobiology, Duke University Medical Center, Durham, NC 27710, USA.
Kelly
Bridget B
BB
Albrecht
Douglas E
DE
Adams
Marvin E
ME
Froehner
Stanley C
SC
Feng
Guoping
G
D000818:Animals; D015152:Blotting, Northern; D049029:Dystrophin-Associated Proteins / Q000235:genetics*; D005091:Exons; D017353:Gene Deletion; D007150:Immunohistochemistry; D051379:Mice; D008817:Mice, Mutant Strains; D009469:Neuromuscular Junction / Q000378:metabolism*; D009479:Neuropeptides / Q000235:genetics*; D010641:Phenotype; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction
C098884:Dtna protein, mouse; D049029:Dystrophin-Associated Proteins; D009479:Neuropeptides; D020033:Protein Isoforms; D012333:RNA, Messenger; C098885:dystrobrevin