Organelle Involved in Gene Silencing Identified

A new study by a team of geneticists at the University of California has come closer to finding how microRNAs repress, or "silence", target gene expression in cells.  An article in Science Daily describes how the geneticists determined that the endoplasmic reticulum  is the site of all microRNA activity repressing gene expression by studying plant cells.  Until now, no one has known in which organelle microRNa activity takes place.  The research has also found the the protein AMP1, found on the inside of the endoplasmic reticulum is integral to the success of the microRNA activity.  Since microRNAs were first identified 20 years ago, much has been learned about them leading to this discovery.

There are two ways in which microRNAs work, by destabilizing the target RNAs, leading to their degradation, or prevent the target RNAs from being translated into proteins through translation inhibition.  The revelation that the ER is the translational inhibition helps scientists to understand gene silencing.  The AMP1 protein is found to be mostly in the rough ER, as opposed to the smooth ER.  The rough ER will be studied more in the future for geneticists to understand exactly how microRNAs and translation inhibition work to stop gene expression.  The article from Science Mag offers more information on the role of microRNA in translation inhibition.