Junk DNA: goodbye! (Introduction)

by David Turell , Monday, January 20, 2014, 15:00 (3747 days ago) @ David Turell

Long non-coding RNA has function:-"In the second phase of the research, a comparison among the different species allowed the scientists to pinpoint the emergence of these genes in the evolutionary history. While 11,000 long non-coding RNAs are shared by all primates, 2,500 go back to an ancestor common to man and mouse, about 90 million years ago. Only a hundred genes of this kind stem from an ancestor common to all eleven species considered, including birds and amphibians. "One of our main findings is that the activity of these non-coding genes is controlled by the same transcription factors that regulate protein-coding gene activity. Even more strikingly, we found that the 2,500 oldest long noncoding RNA genes are regulated by factors that are important for embryonic development. This suggests that, among the 2500 long non-coding RNAs conserved during the evolution of placental mammals, a large percentage may function specifically in embryonic development."
 
New network of interactions
 
The third phase of the research allowed the scientists to highlight a network of interactions (specifically, co-expression interactions, that is: genes are activated in the same organs or cell types) involving both long non-coding RNAs and protein-coding genes. For instance, they found that some non-coding genes are strongly associated to protein coding genes involved in brain function or in spermatogenesis, which suggests similar functions for these long non-coding RNA genes.
 
In the case of the H19X gene - one of the most ancient long noncoding RNA genes identified in this study - its association to the placental mammals' H19 gene (which was the first long non-coding RNA identified years ago) helped to uncover its functioning: "The H19 prevents the placenta from excessively growing inside the mother's womb," said Anamaria Necsulea. "We can assume that H19X also contributes to this function. We now plan to disable this gene in mice to test its functions in the placenta."
 
Among the subcategories of RNA producing genes, are these long RNA genes more useful than it originally seemed? By tracking them in 11 different species, this new study of unprecedented scale suggests that some of our genomes' "dark matter" may play a role in the development and functioning of the most vital organs of our bodies. Future experimental studies will further clarify the role of these genes that have just revealed their first secrets to us."-
 Read more at: http://phys.org/news/2014-01-scientists-biological-dark.html#jCp