Related Experiment Video
Updated: May 10, 2026

Analysis of the c-KIT Ligand Promoter Using Chromatin Immunoprecipitation
Published on: June 27, 2017
A polymorphism in the CTGF promoter region associated with systemic sclerosis
Carmen Fonseca1, Gisela E Lindahl, Markella Ponticos
1Centre for Rheumatology, Royal Free and University College Medical School, London, United Kingdom.
Background:
Systemic sclerosis (scleroderma) is a life-threatening autoimmune disease that is characterized by the presence of specific autoantibodies and fibrosis of the skin and major internal organs.
Methods:
We genotyped a polymorphism (G-945C) in the promoter of the connective-tissue growth factor (CTGF) gene in 1000 subjects in two groups: group 1, consisting of 200 patients with systemic sclerosis and 188 control subjects; and group 2, consisting of 300 patients with systemic sclerosis and 312 control subjects. The combined groups represented an estimated 10% of patients with systemic sclerosis in the United Kingdom. We tested the effect of the polymorphism on the transcription of CTGF.
Results:
The GG genotype was significantly more common in patients with systemic sclerosis than in control subjects in both groups, with an odds ratio for the combined group of 2.2 (95% confidence interval [CI], 1.5 to 3.2; P<0.001 for trend). Analysis of the combined group of patients with systemic sclerosis showed a significant association between homozygosity for the G allele and the presence of anti-topoisomerase I antibodies (odds ratio, 3.3; 95% CI, 2.0 to 5.6; P<0.001) and fibrosing alveolitis (odds ratio, 3.1; 95% CI, 1.9 to 5.0; P<0.001). We observed that the substitution of cytosine for guanine created a binding site of the transcriptional regulators Sp1 and Sp3. The C allele has high affinity for Sp3 and is associated with severely reduced transcriptional activity. A chromatin immunoprecipitation assay showed a marked shift in the ratio of Sp1 to Sp3 binding at this region, demonstrating functional relevance in vivo.
Conclusions:
The G-945C substitution represses CTGF transcription, and the -945G allele is significantly associated with susceptibility to systemic sclerosis.
Related Concept Videos
Pleiotropy
Single Nucleotide Polymorphisms-SNPs
TGF - β Signaling Pathway
Cystic Fibrosis: Pathogenesis
CF is primarily caused by a genetic mutation in a chromosome 7 gene coding for the cystic fibrosis transmembrane conductance regulator (CFTR) protein. The most common gene mutation leading to CF is the ΔF508 mutation, but...
Pharmacogenetic Phenotypes: Alterations in Pharmacokinetics, Drug Targets and Biologic Milieu
Pharmacogenetics of Drug Targets: β₂-Adrenergic Receptors, Apo E, Thymidylate Synthase

