From zero to hero

Scientists have found a new way to switch off genes involved in cell division and in doing so have fuelled a debate over the role of ‘junk’ DNA.

tRNA (pictured) has a well understood function, but other forms of RNA may be much more important than previously thought

The Human Genome Project identified about 34,000 genes responsible for producing proteins. The remaining part - in fact, most of the genome - constituted what was considered to be ‘junk’ DNA with no function. However, latest estimates show that this ‘junk’ DNA produces around half a million varieties of RNA with unknown functions.

“There’s been a quiet revolution taking place in biology during the past few years over the role of RNA,” says Dr Alexandre Akoulitchev, a Senior Research Fellow at the University of Oxford. “Scientists have begun to see ‘junk’ DNA as having a very important function. The variety of RNA types produced from this ‘junk’ is staggering and the functional implications are huge.”

The particular form of RNA that has been of interest to Dr Akoulitchev's team is involved in regulation of the dihydrofolate reductase gene (DHFR). “Inhibiting the DHFR gene could help prevent the growth of neoplastic cancerous cells, ordinary cells which develop into tumour cells, such as in prostate cancer cells,” explains Dr Akoulitchev. “In fact, the first anti-cancer drug, Methotrexate, acts by binding and inhibiting the enzyme produced by this gene.”

Dr Akoulitchev’s findings suggest that ‘junk’ DNA might not be as superfluous as previously thought, and he hopes that they will have important therapeutic implications for the treatment of cancer.