Tiny gene segments called "microexons" manipulate how proteins mingle with each other in the nervous system, which has opened up new avenues of research into autism, according to Medical Xpress.
Scientists at the University of Toronto discovered that microexons are used in neurons by "alternative splicing, a process in which a single gene can produce many different proteins." Microexons are basically cut-and-pasted into RNA (the messenger of DNA) to create proteins that the nervous system uses in normal functions.
"We're seeing a new landscape of splicing regulation that is highly specific to the nervous system, and which is very important for controlling how proteins interact with each other," said Benjamin Blencowe, a professor in the University of Toronto's Donnelly Centre for Cellular and Biomolecular Research and Department of Molecular Genetics. "In addition, a large number of the microexons we detected show misregulation in people with autism."
In the most recent study, Blencowe and his colleagues, led by postdoctoral fellow Manuel Irimia, produced a computational tool that identifies more splices.
"We were really surprised to find that some microexons encode just 1 or 2 amino acids-the basic building blocks of proteins," said Irimia, a junior group leader at the Centre for Genomic Regulation in Barcelona, Spain. "And they modify proteins-changing their surface structures-in ways that longer exons cannot. Microexons perform a type of microsurgery on proteins to alter their function."
Researchers found that the role of microexons is so exact, that if microexons were deleted, proteins would completely lose the ability to interact with other proteins. They also found that a lot of neuronal microexons are poorly pasted into the brains of people with autism because of a weak splicing protein called nSR100, according to Medical Xpress.
"While a lot more work has to be done to understand the functions of microexons in the nervous system, we were amazed by the extent to which microexons are misregulated in people with autism, which suggests they are an important component of this neurological disorder," Blencowe said.
"Microexons are an underappreciated class of splicing event that is highly conserved. They change the way 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."
The findings were published in the journal Cell.
