A novel type 2 diabetes risk allele increases the promoter activity of the muscle-specific small ankyrin 1 gene.
Genome-wide association studies have identified Ankyrin-1 (ANK1) as a common type 2 diabetes (T2D) susceptibility locus. However, the underlying causal variants and functional mechanisms remain unknown. We screened for 8 tag single nucleotide polymorphisms (SNPs) in ANK1 between 2 case-control studies. Genotype analysis revealed significant associations of 3 SNPs, rs508419 (first identified here), rs515071, and rs516946 with T2D (P < 0.001). These SNPs were in linkage disequilibrium (r(2) > 0.80); subsequent analysis indicated that the CCC haplotype associated with increased T2D susceptibility (OR 1.447, P < 0.001). Further mapping showed that rs508419 resides in the muscle-specific ANK1 gene promoter. Allele-specific mRNA and protein level measurements confirmed association of the C allele with increased small ANK1 (sAnk1) expression in human skeletal muscle (P = 0.018 and P < 0.001, respectively). Luciferase assays showed increased rs508419-C allele transcriptional activity in murine skeletal muscle C2C12 myoblasts, and electrophoretic mobility-shift assays demonstrated altered rs508419 DNA-protein complex formation. Glucose uptake was decreased with excess sAnk1 expression upon insulin stimulation. Thus, the ANK1 rs508419-C T2D-risk allele alters DNA-protein complex binding leading to increased promoter activity and sAnk1 expression; thus, increased sAnk1 expression in skeletal muscle might contribute to T2D susceptibility.
School of Medicine, Nanjing University, Nanjing, 210093, China.|Department of Endocrinology, Jinling Hospital Affiliated to Nanjing University School of Medicine, Nanjing, 210002, China.|Department of Endocrinology, Nanjing First Hospital Affiliated to Nanjing Medical University, Nanjing, 210006, China.
Rengna
R
Yan
School of Medicine, Nanjing University, Nanjing, 210093, China.|MOE Key Laboratory of Model Animals for Disease Study, Model Animal Research Center and the School of Medicine, Nanjing University, National Resource Center for Mutant Mice, Nanjing 210093, China.|Jiangsu Key Laboratory of Molecular Medicine, Nanjing, 210002, China.
Shanshan
S
Lai
School of Medicine, Nanjing University, Nanjing, 210093, China.|Jiangsu Key Laboratory of Molecular Medicine, Nanjing, 210002, China.|Department of Urology, Drum Tower Hospital Affiliated to Nanjing University School of Medicine, Nanjing, 210008, China.
Yang
Y
Yang
School of Medicine, Nanjing University, Nanjing, 210093, China.|Jiangsu Key Laboratory of Molecular Medicine, Nanjing, 210002, China.|Department of Orthopedics, Drum Tower Hospital Affiliated to Nanjing University School of Medicine, Nanjing, 210008, China.
Hongfei
H
Shi
School of Medicine, Nanjing University, Nanjing, 210093, China.|Jiangsu Key Laboratory of Molecular Medicine, Nanjing, 210002, China.
Zhenming
Z
Cai
Molecular Medicine Section, Department of Molecular and Developmental Medicine, University of Siena, Siena, 53100, Italy.
Vincenzo
V
Sorrentino
School of Medicine, Nanjing University, Nanjing, 210093, China.|Department of Endocrinology, Jinling Hospital Affiliated to Nanjing University School of Medicine, Nanjing, 210002, China.
Hong
H
Du
School of Medicine, Nanjing University, Nanjing, 210093, China.|Jiangsu Key Laboratory of Molecular Medicine, Nanjing, 210002, China.
Huimei
H
Chen
D000328:Adult; D000368:Aged; D000818:Animals; D017487:Ankyrins / Q000235:genetics* / Q000378:metabolism; D003924:Diabetes Mellitus, Type 2 / Q000235:genetics / Q000378:metabolism*; D005260:Female; D015870:Gene Expression; D056726:Genetic Association Studies; D020022:Genetic Predisposition to Disease; D005947:Glucose / Q000378:metabolism; D006239:Haplotypes; D006801:Humans; D007328:Insulin / Q000378:metabolism; D008297:Male; D051379:Mice; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000378:metabolism*; D020641:Polymorphism, Single Nucleotide
C110202:ANK1 protein, human; D017487:Ankyrins; D007328:Insulin; D005947:Glucose