Related Experiment Video
Updated: Jul 5, 2026

Correlating Gene-specific DNA Methylation Changes with Expression and Transcriptional Activity of Astrocytic KCNJ10 (Kir4.1)
Published on: September 26, 2015
Age influences DNA methylation and gene expression of COX7A1 in human skeletal muscle
1Department of Clinical Sciences, CRC Malmö University Hospital, Lund University, 205 02, Malmö, Sweden.
Aims/Hypothesis:
Reduced oxidative capacity of the mitochondria in skeletal muscle has been suggested to contribute to insulin resistance and type 2 diabetes. Moreover, a set of genes influencing oxidative phosphorylation (OXPHOS) is downregulated in diabetic muscle. Here we studied whether genetic, epigenetic and non-genetic factors influence a component of the respiratory chain, COX7A1, previously shown to be downregulated in skeletal muscle from patients with type 2 diabetes. The specific aims were to: (1) evaluate the impact of genetic (single nucleotide polymorphisms [SNPs]), epigenetic (DNA methylation) and non-genetic (age) factors on the expression of COX7A1 in human skeletal muscle; and (2) investigate whether common variants in the COX7A1 gene are associated with increased risk of type 2 diabetes.
Methods:
COX7A1 mRNA expression was analysed in muscle biopsies from young (n = 110) and elderly (n = 86) non-diabetic twins and related to measures of in vivo metabolism. Genetic variants (three SNPs) from the COX7A1 locus were genotyped in the twins and in two independent type 2 diabetes case-control cohorts (n = 1466 and 6380, respectively). DNA methylation of the COX7A1 promoter was analysed in a subset of twins (ten young, ten elderly) using bisulphite sequencing.
Results:
While DNA methylation of the COX7A1 promoter was increased in muscle from elderly compared with young twins (19.9 +/- 8.3% vs 1.8 +/- 2.7%; p = 0.035), the opposite was found for COX7A1 mRNA expression (elderly 1.00 +/- 0.05 vs young 1.68 +/- 0.06; p = 0.0005). The heritability of COX7A1 expression was estimated to be 50% in young and 72% in elderly twins. One of the polymorphisms investigated, rs753420, influenced basal COX7A1 expression in muscle of young (p = 0.0001) but not of elderly twins. The transcript level of COX7A1 was associated with increased in vivo glucose uptake and VO(2max) (p = 0.009 and p = 0.001, respectively). We did not observe any genetic association between COX7A1 polymorphisms and type 2 diabetes after correcting for multiple testing.
Conclusions/Interpretation:
Our results provide further evidence for age as a factor influencing DNA methylation and expression of OXPHOS genes, and thereby in vivo metabolism.
Related Concept Videos
Epigenetic Regulation
X-chromosome...
Epigenetic Regulation
Genomic Imprinting and Inheritance
The expression of some genes depends on which parent passed the gene to the offspring, through a phenomenon known as...
Master Transcription Regulators
Histone Modification
Acetylation
The enzyme histone acetyltransferase adds acetyl group to the histones. Another enzyme, histone deacetylase,...
Formation of Muscle Fibers from Myoblasts
Muscle progenitor cells (MPCs) are formed from the myotomes. MPCs express genes that encode the transcription factors Pax3 and Pax7. Along with Pax 3/7, other transcription factors...

