Evaluation of the effect of a floxed Neo cassette within the dystroglycan (Dag1) gene.

Objective: Dystroglycan (DG) is an adhesion complex formed by two subunits, α-DG and β-DG. In skeletal muscle, DG is part of the dystrophin-glycoprotein complex that is crucial for sarcolemma stability and it is involved in a plethora of muscular dystrophy phenotypes. Due to the important role played by DG in skeletal muscle stability as well as in a wide variety of other tissues including brain and the peripheral nervous system, it is essential to investigate its genetic assembly and transcriptional regulation.
Results: Herein, we analyze the effect of the insertion of a floxed neomycin (Neo) cassette within the 3' portion of the universally conserved IG1-intron of the DG gene (Dag1). We analyzed the transcription level of Dag1 and the expression of the DG protein in skeletal muscle of targeted mice compared to wild-type and we did not find any alterations that might be attributed to the gene targeting. However, we found an increase of the cross-sectional areas of tibialis anterior that might have some physiological significance that needs to be assessed in the future. Moreover, in targeted mice the skeletal muscle morphology and its regeneration capacity after injury did not show any evident alterations. We confirmed that the targeting of Dag1 with a floxed Neo-cassette did not produce any gross undesired effects.