HIF-1α regulates SLC11A1 allele expression phenotypes from the cognate microsatellites. (A) Alignment of microsatellites of SLC11A1 alleles identified in different (human) individuals and populations. HIF-1α response elements (TACGTG) are underlined. Note HREb deletion or mutation in alleles 4 and 7, respectively; the control (nonnatural) mutant microsatellite (GT)22 is also shown for comparison. Nucleotides (not shown) juxtaposing either side of each microsatellite are identical. Using allele 1 as reference, dashes indicate deletions, red-coded nucleotides are identical residues, green-coded residues are conserved in at least 5 alleles, and black prints indicate nonconserved residues. (B) One hundred nanograms each of allele-specific promoter constructs derived by microsatellite interchange were transfected alone or with 100 ng HIF-1α expression vector. Allele 3 microsatellite (a3) was interchanged (*) with microsatellites of alleles 1 (a1), 2 (a2), 6 (a6), and 7 (a7). Regulatory SNPs in allele 2 (a3*a2TG and a3*a2CG) and allele 3 (a3TG*a3CG) were also generated. The mutant HRE-null microsatellite a3*GT22 carried the a3CG SNP, and a3delHREa is allele 3 with a mutated NR1HREa. Fold activation is with respect to pGL3Basic. Results are representative of 5 experiments (means ± SEM).
