Alternative splicing regulates the nuclear or cytoplasmic localization of dystrophin Dp71

The subcellular distribution of Dp71 isoforms alternatively spliced for exon 71 and/or 78 was examined. The cDNA sequence of each variant was fused to the C-terminus of the green fluorescent protein and the constructs were transfected transiently in the cell lines HeLa, C2C12 and N1E-115. The subcellular distribution of the fused proteins was determined by confocal microscope analysis. The Dp71 isoform lacking the amino acids encoded by exons 71 and 78 was found exclusively in the cytoplasm whereas the variants containing the amino acids encoded by exon 71 and/or exon 78 show a predominant nuclear localization. The nuclear localization of Dp71 provides a new clue towards the establishment of its cellular function.