Posts tagged splicing
Articles and news from the latest research reports.
Neurons at work
Film editors play a critical role by helping shape raw footage into a narrative. Part of the challenge is that their work can have a profound impact on the finished product — with just a few cuts in the wrong places, comedy can become tragedy, or vice versa.
A similar process, “alternative splicing,” is at work inside the bodies of billions of creatures — including humans. Just as a film editor can change the story with a few cuts, alternative splicing allows cells to stitch genetic information into different formations, enabling a single gene to produce up to thousands of different proteins.
Harvard scientists say they’ve now been able to observe that process within the nervous system of a living creature.
Evolution: It’s all in how you splice it
MIT biologists find that alternative splicing of RNA rewires signaling in different tissues and may often contribute to species differences.
When genes were first discovered, the canonical view was that each gene encodes a unique protein. However, biologists later found that segments of genes can be combined in different ways, giving rise to many different proteins.
This phenomenon, known as alternative RNA splicing, often alters the outputs of signaling networks in different tissues and may contribute disproportionately to differences between species, according to a new study from MIT biologists.
After analyzing vast amounts of genetic data, the researchers found that the same genes are expressed in the same tissue types, such as liver or heart, across mammalian species. However, alternative splicing patterns — which determine the segments of those genes included or excluded — vary from species to species.
“The core things that make a heart a heart are mostly determined by a heart-specific gene expression signature. But the core things that make a mouse a mouse may disproportionately derive from splicing patterns that differ from those of rats or other mammals” says Chris Burge, an MIT professor of biology and biological engineering, and senior author of a paper on the findings in the Dec. 20 online edition of Science.
Lead author of the paper is MIT biology graduate student Jason Merkin. Other authors are Caitlin Russell, a former technician in Burge’s lab, and Ping Chen, a visiting grad student at MIT.
Researchers uncover major source of evolutionary differences among species
University of Toronto Faculty of Medicine researchers have uncovered a genetic basis for fundamental differences between humans and other vertebrates that could also help explain why humans are susceptible to diseases not found in other species.
Scientists have wondered why vertebrate species, which look and behave very differently from one another, nevertheless share very similar repertoires of genes. For example, despite obvious physical differences, humans and chimpanzees share a nearly identical set of genes.
The team sequenced and compared the composition of hundreds of thousands of genetic messages in equivalent organs, such as brain, heart and liver, from 10 different vertebrate species, ranging from human to frog. They found that alternative splicing — a process by which a single gene can give rise to multiple proteins — has dramatically changed the structure and complexity of genetic messages during vertebrate evolution.
The results suggest that differences in the ways genetic messages are spliced have played a major role in the evolution of fundamental characteristics of species. However, the same process that makes species look different from one another could also account for differences in their disease susceptibility.
"The same genetic mechanisms responsible for a species’ identity could help scientists understand why humans are prone to certain diseases such as Alzheimer’s and particular types of cancer that are not found in other species," says Nuno Barbosa-Morais, the study’s lead author and a computational biologist in U of T Faculty of Medicine’s Donnelly Centre for Cellular and Biomolecular Research. "Our research may lead to the design of improved approaches to study and treat human diseases."
One of the team’s major findings is that the alternative splicing process is more complex in humans and other primates compared to species such as mouse, chicken and frog.
"Our observations provide new insight into the genetic basis of complexity of organs such as the human brain," says Benjamin Blencowe, Professor in U of T’s Banting and Best Department of Research and the Department of Molecular Genetics, and the study’s senior author.
"The fact that alternative splicing is very different even between closely related vertebrate species could ultimately help explain how we are unique."