Analysis of the promoter regions of disease-causing genes in maturity-onset diabetes of the young patients

Abstract

Maturity-onset diabetes of the young (MODY) is a form of monogenic diabetes caused by the variants in MODY-related genes. In addition to coding variants, variants in the promoter region of MODY-related genes can cause the disease as well. In this study, we screened the promoter regions of the most common MODY-related genes GCK, HNF1A, HNF4A and HNF1B in our cohort of 29 MODY patients. We identified one genetic variant in the HNF1A gene, a 7 bp insertion c.-154-160insTGG GGG T, and three variants in the GCK gene, −282C>T; −194A>G; 402C>G appearing as set. Chloramphenicol acetyltransferase (CAT) assay was performed to test the effect of the 7 bp insertion and the variant set on the activity of the reporter gene in HepG2 and RIN-5F cell, respectively, where a decreasing trend was observed for both variants. In silico analysis and electrophoretic mobility shift assay showed that the 7 bp insertion did not create the binding site for new transcriptional factors, but gave rise to additional binding sites for the existing ones. Results from our study indicated that the 7 bp insertion in the HNF1A gene could be associated with the patient's diabetes. As for the GCK variant set, it is probably not associated with diabetes in patients, but it may modify the fasting glucose level by causing small elevation in variant set carriers. We have presented two promoter variants in MODY-related genes. Variant in the HNF1A gene is presumed to be disease-causing and the GCK promoter variant set could be a phenotype modifier. Keywords Maturity-onset diabetes of the young (MODY) • HNF1A gene • GCK gene • Promoter variants • Functional analysis

Rutaecarpin reduces lipids by DGKθ‐dependent activation of PPARα

“…To explore the effect of HNF1B on the biological activity of the DGKθ promoter, a 1.6‐kilobase human DGKθ promoter (−1130 + 331 nucleotide) [19] was amplified and subcloned in pGL3‐Basic (Promega); the obtained plasmid was named pGL3‐Basic‐DGKθ‐promoter (DGKθp). Next, pCDNA3.1‐HNF1B and pGL3‐Basic‐DGKθp were co‐transfected into HepG2 cells; 24 hours post transfection, the luciferase activity was assayed by a luciferase assay kit (Promega).…”

Stem Cell-Derived β Cells: A Versatile Research Platform to Interrogate the Genetic Basis of β Cell Dysfunction

“…Non-coding variants that fall near transcriptional start sites have significantly larger eQTL effects compared to those found in distal enhancers [ 273 ]. Some variants with substantial expression effects are associated with MODY, such as promoter mutations in GCK , HNF1A or HNF4A [ 268 , 274 , 275 , 276 , 277 , 278 , 279 , 280 ] or neonatal diabetes with SNPs in the CC element of the INS promoter [ 281 , 282 ]. GWAS-identified SNPs in loci associated with altered promoter activity include ARAP1 [ 283 ], G6PC2 [ 284 , 285 ] or the T1D-candidate gene CTSH [ 286 ].…”

Reanálise fenotípica e genotípica de indivíduos com diagnóstico clínico de diabetes monogênico sem etiologia molecular estabelecida

“…Do ponto de vista de DM monogênico, a análise de regiões regulatórias tem se mostrado promissora 53 , como esperado. Variantes em região promotora já são descritas em genes mais comumente associados a MODY (HNF1A 45,[54][55][56] , GCK 57,58 , HNF4A 45,59 ).…”