Limitations of the Pax7-creER(T2) transgene for driving deletion of Nf1 in adult mouse muscle.

In this study, we present the characterization of an inducible muscle-specific NF1 knockout strain (Nf1Pax7i f/f ) produced by cross breeding the Pax7-CreER(T2) strain with the conditional Nf1flox/(flox) line. Tamoxifen dosing of 8-week old Nf1Pax7i f/f mice led to recombination of the floxed allele in muscle, as detected by PCR. Detailed phenotypic analysis of treated adult mice over 8 weeks revealed no changes in bodyweight or muscle weight, no histological signs of myopathy, and no functional evidence of distress or impairment. Subsequent analysis using the Ai9 Cre-dependent tdTomato reporter strain was used to analyse labelling in embryos and in adult mice. Cell tracking studies identified a lower than expected rate of integration of recombined satellite cells into adult muscle. In contrast, a high persistent contribution of embryonic cells that were Pax7+ were found in adult muscle. These findings indicate important caveats with the use of the Pax7-CreER (T2) strain and highlight a need to develop new tools for investigating the function of NF1 in mature muscle. PMID: 29139538 [PubMed - in process]
Source: International Journal of Developmental Biology - Category: Biology Tags: Int J Dev Biol Source Type: research