CELF1 and myotonic dystrophy type 1: In line with this observation, sarcomere size is still reduced in the DM1960,Df(bru-3) line, as it is in the DM1960 line, which indicates that Bru-3 is not involved in the hypercontracted muscle phenotype in the Drosophila model of DM1, much like its vertebrate counterpart, CELF1 (Ward et al., 2010).