Dystrophin and Dp71, two products of the DMD gene, show a different pattern of expression during embryonic development in zebrafish

Dystrophin, the protein defective in Duchenne muscular dystrophy (DMD), pla ys a critical role in the formation and maintenance of the neuromuscular ju nction. In addition to dystrophin, activation of internal promoters of the DMD gene leads to the production of several short products. Among these, Dp 71, which consists of the C-terminal domain of dystrophin, is the most abun dant product of the gene in nonmuscle tissues and brain. In this report, we compare the temporal and regional expression patterns of dystrophin and Dp 71 at different stages of embryonic development and during retinal differen tiation in zebrafish. The Dp71 transcripts are the earliest to be expressed at 9-10 h post-fertilization (hpf) in the axial mesoderm. As development p roceeds, intense Dp71 staining is observed in the notochord, the developing brain, the marginal regions of the somites and the eye primordium. At the completion of retinal differentiation, Dp71 is expressed in the ganglion an d inner nuclear layers. Transcripts encoding dystrophin have a slightly lat er onset of expression, 13-14 hpf. and remain restricted to the transverse myosepta through all the developmental stages examined. The complementary p atterns of expression of dystrophin and Dp71 suggest that these two protein s exert different functions during embryonic development in zebrafish. (C) 2001 Elsevier Science Ireland Ltd. All rights reserved.