The genomic structure of the mouse gene encoding the CDEBP protein has been established. The protein was initially identified on the basis of its ability to bind the CDEI motif (GTCACATG). The same locus has been independently described under the name APLP2, on the basis of sequence similarities with the Amyloid Precursor Protein (APP). The exon-intron distribution of Cdebp appears strikingly similar to that of the App gene in the regions encoding the conserved domains, with a divergent structure in the other parts. The transcription start site has been localized, and sequences with promoter activity have been identified immediately upstream of it by their ability to direct the expression of a reporter luciferase gene in transfected cells. This region is devoid of either TATA or CAAT boxes. The gene has been mapped to mouse chromosome 9 by in situ hybridization on metaphase chromosomes.