Stefan Janusz reports :: March 2008

The instructions in DNA are sent out from the nucleus — the cell's control centre — to the cellular machinery, such as the ribosomes that build a cell's protein components, using messenger RNA (mRNA), a molecule similar to DNA but with a simpler, single-stranded structure. A team led by Rebecca Oakey at King's College London has described in a recent paper how the degree of DNA methylation for a particular mouse gene can affect the position of the 'tagging' site of  mRNA, which stabilises the molecule as it is transferred into the cell, and also provides a starting point for the list of instructions it carries. The sites are long repeat sequences of adenine, 'A' in the genetic code.  This is the first time methylation-based epigenetic imprinting has been shown to affect the relay of the genetic instructions in this way.