Exons and functional regions of the human vitamin D receptor gene around and within the main 1a promoter are well conserved among mammals

The human vitamin D receptor (hVDR) gene encompasses eight exons (2-9) in the so-called coding region and six more exons (1a-1f) in the so-called regulatory region, which contains several reported promoters. Evolutionary comparison performed on the VDR promoter sequences of a dozen of mammalian species shows a very high conservation of numerous regions around and in the 1a promoter, including exons 1e, 1a and 1d. and the Sp1 site region. This suggests that the so-called 1a promoter is well conserved among mammals. Homology among mammals also concerns three functional SNP site regions of the hVDR 1a promoter, the 1e-G-1739A SNP region (a Cdx-2 binding site). and both 1a-G-1521 C and 1a-A-1012G sites, the 1a-1012A being located within a GATA site. Interestingly, the 1521G and 1012A nucleoticles are being evolutionary conserved, suggesting that the 1521C/1012G haplotype, which is found in human chromosomes (43 % of Caucasians), is a human specificity. (c) 2006 Elsevier Ltd. All rights reserved.