I'm not sure if this quite fulfills your criteria, but expression of the mammalian MAP 2 gene produces either a ca. 210 kDa protein (MAP 2A or MAP 2B) or a 70 kDa protein (MAP 2 C) which is "missing" the middle 140 kDa of the larger coding sequence. These are all made from the same gene, but differentially spliced. Bob Obar