microRNA belong to the non-coding region of the genome. They play a very important role in regulating the other gene activities like synapses. Researchers at Children's Hospital, Boston says that they are involved in the development of the nervous system. Synapses are the junctions where the brain cells communicate with each other. This region is very important in the process of developing learning and memory. The findings of this research were published in the journal Nature.
Michael Greenberg, PhD, Director of Neuroscience at Children's Hospital Boston said that this research is one of a kind that helps us to probe into the new mechanism of gene regulation and expression.
Brain has the ability to make or break new synapses thereby adapting itself to the changing environment. It helps in the strengthening the new synaptic junctions and breaking the old unnecessary ones.
Greenberg experimented with animal models such as the rat said that miR-134 (microRNA) helps in altering the size of dendritic spines. Synapses occur at the junction of these dendrites. miR-134 decreases the spine size and weakens the synapse. When miR-134 was inhibited, spines increased in size, strengthening the synapse.
miR-134 is responsible for the inhibition of a gene, Limk1. This causes the growth of the dendritic spines. When neurons were exposed to a growth factor, brain-derived neurotrophic factor (BDNF), Limk1 became active again, enhancing spine growth.
Greenberg believes that the microRNA are responsible in controlling synaptic development. A single neuron can give rise to thousands of synapses. He says that it is very important to be able to control the activities at one synaptic junction without altering the activities at another junction. By doing so a person has the ability to store more information and have increased computational capacity in the brain.
He thinks that this discovery can be put to use in case of treating disorders such as mental retardation and autism. It is found that deletion of Limk1 gene is associated with Williams syndrome, and that the alteration of the BDNF pathway all are found in case of patients suffering from tuberous sclerosis and Fragile X syndrome. Research is proved that these three disorders lead to mental retardation and compromised cognition.