Doubling the information from the Double Helix

These findings are important as they show that very small changes in miRNA genes will have a dramatic effect on brain function and may influence our memory function or likelihood of developing neurodegenerative diseases. These findings also suggest that many more human mirror microRNAs will be found and that they could ultimately be used as treatments for human neurodegenerative diseases such as dementia.

Our genes control many aspects of who we are -- from the colour of our hair to our vulnerability to certain diseases -- but how are the genes, and consequently the proteins they make themselves controlled?  Researchers have discovered a new group of molecules which control some of the fundamental processes behind memory function and may hold the key to developing new therapies for treating neurodegenerative diseases.

The research, led by academics from the University of Bristol’s Schools of Clinical Sciences , Biochemistry and Physiology & Pharmacology and published in the Journal of Biological Chemistry , has revealed a new group of molecules, called mirror-microRNAs.

MicroRNAs are non-coding genes that often reside within ’junk DNA’ and regulate the levels and functions of multiple target proteins -- responsible for controlling cellular processes in the brain. The study’s findings have shown that two microRNA genes with different functions can be produced from the same piece (sequence) of DNA -- one is produced from the top strand and another from the bottom complementary ’mirror’ strand.

Specifically, the research has shown that a single piece of human DNA gives rise to two fully processed microRNA genes that are expressed in the brain and have different and previously unknown functions. One microRNA is expressed in the parts of nerve cells that are known to control memory function and the other microRNA controls the processes that move protein cargos around nerve cells.

James Uney, Professor of Molecular Neuroscience in the University’s School of Clinical Sciences, said: "These findings are important as they show that very small changes in microRNA genes will have a dramatic effect on brain function and may influence our memory function or likelihood of developing neurodegenerative diseases. These findings also suggest that many more human mirror microRNAs will be found and that they could ultimately be used as treatments for human neurodegenerative diseases such as dementia."