Fig. 3. Alternative splicing of Filia in mice. (A) (a) Filia is a single-copy gene with three exons on chromosome 9 (73,235,088-73,237,040) that is transcribed as two isoforms. (b) The less abundant 1.6 kb transcript encodes a 440 amino acid protein with a smaller molecular mass (48 kDa) than predicted (70 kDa) by its mobility on SDS-PAGE. The tenfold repeat is indicated by double-arrow line, and peptides obtained by mass spectrometry (yellow rectangles) are aligned at the bottom. (c) Same as b for the 1.2 kb transcript that encodes a 346 amino acid protein with a smaller molecular mass (38 kDa) than predicted (50 kDa) by its mobility on SDS-PAGE. (B) Synthetic oligonucleotide primers and Taqman probes designed to distinguish the alternatively spliced 1.6 kb (upper) and 1.2 kb (lower) isoforms of Filia transcripts. E, exon.