A really interesting story has been circulating in the press this week on the effects of intense exercise on the levels of gene expression in the cell.
The study, conducted by Professor Zierath and her team based at the Karolinska Institutet in Stockholm, Sweden, shows that certain genes linked to respiration and metabolism, can be ‘turned on’ by a bout of intense exercise.
This reversal is achieved by removing certain chemical groups, called ‘methyl groups’ from the bases which form the promoter region of DNA. This allows RNA polymerase to successfully transcribe the gene, resulting in the production of proteins called as ‘transcription factors’.
Transcription factors bind to promoter regions of other genes, and turn them ‘on’. The sum effect is the increased uptake and metabolism of glucose.
The study is interesting in itself because very little is know about reversing methylation patterns – the assumption has always been that genes once ‘turned off’ or ‘slowed down’ cannot be returned to their original state. These results show that our genome is more flexible and adaptable that we previously thought.
The effects observed, however, were only short term. DNA methylation patterns soon returned to their original levels. Interestingly, when rat muscle cells were exposed to caffeine and stimulated to contract in the laboratory, a similar demethylation effect was observed.
Stimulation of muscle cells releases calcium ions from sacroplasmic reticulum, thus the demethylation effects might be triggered by large concentrations of calcium ions in cells.
To mimic the effects seen in muscle cells one would have to consume around 50 cups of coffee – a near lethal dose! Regular exercise on the other hand, can have a range of benefits, apart from a temporary spike in enzyme levels. Though this does not prevent you from combining a cuppa with your workout!
Can exercise change your DNA?, NHS news, March 2012
A trip to the gym alters DNA, Nature News, March 2012
Acute Exercise Remodels Promoter Methylation in Human Skeletal Muscle, Cell metabolism, 15, 405-411, March 2012 [original article on human volunteers]
The Role of Methylation in Gene Expression, Scitable, 2008