A) Northern blot showing the truncated CSMD1 transcript expressed by the SCC9 cell line. Approximately 8 μg of poly-A+ RNA was fractionated on a denaturing 1% agarose gel, transferred to a filter and probed with the full length human CSMD1 cDNA. The image was acquired by phosphorimager scanning. B) Structure of the aberrant SCC9 transcript and the corresponding segment of the wildtype CSMD1 transcript showing the relationship between the novel cryptic promoter and exon 37. The partial Alu element contains only the first 120 base pairs of the normal ~300 bp Alu sequence.