Genomic organization and chromosomal localization of the human CD163 (M130) gene: A member of the scavenger receptor cysteine-rich superfamily

The human protein CD163 (M130) is a member of the scavenger receptor cystei ne-rich (SRCR) superfamily, which is exclusively expressed by monocytes and macrophages. Here, we investigated the genomic organization and the chromo somal localization of the human CD163 gene. The CD163 gene is composed of 1 7 exons and 16 introns and spans over 35 kb. Each of its nine SRCR domains is encoded by a separate exon, which is similar to other members of the gro up B SRCR subfamily. Two cytoplasmic variants of CD163 arise from alternati ve splicing of intron 15, while a truncated and an extracellular variant re sults from alternative splicing of intron 5 or intron 7, respectively. Usin g fluorescence in situ hybridization we mapped this gene to the human chrom osome 12p13. The transcription initiation sites of the CD163 gene were dete rmined and the 5'-flanking region was sequenced. The nucleotide analysis re vealed several putative binding sites for transcription factors, which have been shown to play an important role in myeloid specific gene expression. In addition, we identified a L1 element located 1.4 kb upstream of the majo r transcription initiation site. (C) 1999 Academic Press.