The structure of MTG16 gene. Three P1 clones covering the entire MTG16 gene are shown in the upper part of the figure. Exons of the MTG16 gene are represented by boxes on the restriction map. Horizontal bars indicate breakpoints in t(16;21) patients. Breakpoints in patients 2 and 3 indicate sites predicted from cDNA sequences. Sa, N, E, and Bg indicate the restriction site forSa/I, NotI, EcoRI, and BglII, respectively. Horizontal bars under the restriction map indicates the probes that were used in Southern blot analysis of the genomic DNAs. Schematic representation of alternative splicing forms of theMTG16 transcripts, MTG16a and MTG16b, are also shown. The positions of deduced start codons and stop codons are shown by ATG and TGA, respectively.