Exon 12 of the shot-RH isoform, encoding the shot plakin repeat region (PRR), has been deleted and replaced by a sequence cassette encoding 1. a Disc\RFPDsRed(T1).3xP3.cHa marker flanked by loxP sites and 2. a single attP site. Severe expression changes of other shot exons are seen, suggestive of splice aberrations.