ABSTRACT
The human SLC2A10 gene encodes the high-affinity glucose transporter 10 (GLUT10) and is widely expressed in adult tissues, including organs which play major roles in glucose homeostasis. Its function and genomic location in a region linked to Type 2 diabetes susceptibility are consistent with a potential role in Type 2 diabetes. Analysis of the CpG-rich promoter revealed the presence of two major transcription start points with differential use in tissues and cell lines. Mapping of transcriptionally active regions in the 5' flanking sequence identified a region, located between nucleotides -70 and -14 (relative to the major transcription start point) as the SLC2A10 basal promoter. This sequence harbors consensus binding sites for Sp, AP2alpha, and other transcription factors. A juxtaposed Sp/AP2alpha motif located between -25 and -11 is critical for core promoter function. In cells expressing Sp and AP2 factors, the two motifs are required for maximal activation of the basal promoter. In cells lacking AP2alpha, transcription is dependent on the integrity of the Sp site. Using electrophoresis mobility shift assays, we demonstrate that Sp1 and Sp3 bind to the GC-box in site 5 forming specific complexes. In addition, a silencer region is present upstream of -696 which down-regulates SLC2A10 promoter activity independently of its distance to the transcript start site.
Subject(s)
Gene Expression Regulation , Monosaccharide Transport Proteins/biosynthesis , Monosaccharide Transport Proteins/genetics , Promoter Regions, Genetic , Base Sequence , Blood Glucose/metabolism , Cell Line, Tumor , DNA-Binding Proteins/physiology , Down-Regulation , Gene Silencing , Genes, Reporter , Glucose Transport Proteins, Facilitative , Humans , Luciferases/genetics , Molecular Sequence Data , Sp1 Transcription Factor/physiology , Sp3 Transcription Factor , Transcription Factors/physiologyABSTRACT
A dense gene-based SNP map was constructed across a 360-kb region containing the interleukin-1 gene cluster (IL1A, IL1B, and IL1RN), focusing on IL1RN. In total, 95 polymorphisms were confirmed or identified primarily by direct sequencing. Polymorphisms were precisely mapped to completed BAC and genomic sequences spanning this region. The polymorphisms were typed in 443 case-control subjects from Caucasian and African American groups. Consecutive pair-wise marker linkage disequilibrium was not strictly correlated with distance and ranged from D'=0.0079 to 1.000 and D'=0.0521 to 1.0000 in Caucasians and African Americans, respectively. Single markers and haplotypes in IL1 cluster genes were evaluated for association with end-stage renal disease (ESRD). Eleven SNPs show some evidence of association with ESRD, with the strongest associations in two IL1A variants, one SNP, rs1516792-3, in intron 5 (p=0.0015) and a 4-bp insertion/deletion within the 3'UTR, rs16347-2 (p=0.0024), among African Americans with non-T2DM-associated ESRD.
