All the cells in a human body include same genomic information. Infact, genome is the cell's book of instructions.

"They are very short fragments, some even code for only one or two amino acids, the basic components, or letters, of proteins, but we have observed that these are essential for neurone maturation", explains Manuel Irimia, first author of the work, from the University of Toronto and now group leader in the Centre for Genomic Regulation in Barcelona, Spain. In the same way that a word, even though very short, can change the meaning of a phrase, microexons acheive the same effect and contribute to the creation of proteins with different functions.
Sometimes, the smallest thing is key:
The work published on Thursday 18th December in the journal Cell presents the group of microexons that the scientists have discovered and reveals interesting aspects of these small gene fragments. On the one hand, the researchers have seen that, although microexons are small, they play a very important role in neuron maturation.
"The nervous system is the only place where we have found that the majority of microexons are activated, and we have discovered that they provide important functions in developing neurons", adds Dr Irimia. They have also observed a relationship between these microexons and autism: a great number of the microexons studied are not expressed correctly in individuals with autism, including several microexons in genes that had previously been associated with this disorder.
On the other hand, identifying these microexons and demonstrating their functions provides new information for genome regulation and shakes the foundations of what, up to now, has been known about alternative splicing. "Although until now these short fragments have not been taken into account, we now know that there is another group players who have a lot to say on the matter", state the researchers.
"We're seeing a new landscape of splicing regulation that is highly specific to the nervous system", comments Dr Benjamin Blencowe, Professor in the University of Toronto's Donnelly Centre for Cellular and Biomolecular Research and the Department of Molecular Genetics, and senior author of the study. "Microexons change the way in which proteins interact and clearly play an important role in development, so understanding their role in human neurological disorders represents a major avenue of future research", concludes Blencowe.
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Talent that returns to Spain:
The first author of this work is the Spanish investigator Manuel Irimia who started on the project as a postdoctoral researcher in Blencowe's lab at the University of Toronto. This young scientist has just arrived at the Centre for Genomic Regulation in Barcelona, where he will head up the "Transcriptomics of vertebrate development and evolution" group.
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Dr Irimia has just obtained one of the prestigious "Starting Grants" from the European Research Council (ERC). These grants support outstanding young investigators in their fields so that they can set up their own laboratories and carry out cutting-edge research over a four-year period. Manuel Irimia's project "Functions and evolutionary impact of transcriptomic novelties in the vertebrate brain" looks to understand the functions and evolutionary impact of alternative splicing on the nervous system of vertebrates and has been funded with 1.5 million euros.
Source-Eurekalert