GENOMIC STRUCTURE OF THE HUMAN CD53 GENE

The genomic structure of the gene encoding human pan-leukocyte surface glycoprotein CD53 (a member of the ''tetraspan family'' of membrane p roteins) was determined. The gene consists of eight exons encoding all sequences found in cDNA and is spread over more than 26 kilobases of genomic DNA. The exon-intron organization of the CD53 gene is striking ly similar to the CD63 and TAPA-1 genes, which suggests a close evolut ionary relationship between these genes. The 5' end of the gene upstre am of the first exon contains at least three close transcription start points (approximately 20 base pairs 5' of the 5' end of the published cDNA). The region upstream of the transcription initiation sites is n ot G+C rich; it contains potential binding sites for several transcrip tional factors but no TATA or CCAAT boxes.