Conditionally Immortal Dysferlin-deficient Cell Lines from Mouse Models
We have been breeding mouse lines carrying mutations in the dysferlin gene (A/J and SJL/J). These lines have been crossed with the Immortomouse in order to generate conditionally immortalized myoblasts derived from muscle satellite cells derived from isolated EDL muscle fibers. This is important because many spontaneously immortal mouse cell lines, like C2C12 show major genetic and phenotypic drift such that no two lines in different laboratories are the same. This makes it very difficult to distinguish effects that are specific to clones from effects that are specific to treatments. Because we have no equivalent wild-type strains for either of these dysferlin-mutant strains, we selected the dysferlin+ve F2 progeny of the immortomouse X SJL/J and A/J crosses as the best available sources of wild-type conditionally immortal myoblasts. Recently, we have crossed the immortomouse to the129-Dysftm1Kcam/J dysferlin-deficient mouse line, because it is fully null for dysferlin expression while both the A/J and SJL/J mouse strains have additional mutations that may affect response to muscle injury and both show low level expression of dysferlin or some cross-reacting antigen on Western blots. We have begun examining the newly generated oligoclonal lines of conditionally immortalized myoblasts that are dysferlin-deficient from the AJ and SJL/J mice (and strain-matched controls) by immunocytochemistry for several myogenic markers and to assess fusion potential.