Xing noted that in other circumstances, altering the rate of protein production can cause disease, meaning that a mechanism that can affect protein production can have a real impact on the characteristics of an organism.
"This would not be the only mechanism that might differentiate humans from other primates, but our study suggests that the creation of new exons from Alu elements is an important process that contributes to those differences," Xing said.
The UI team, including co-first authors Shihao Shen, doctoral student in the Department of Biostatistics; and Lan Lin, Ph.D., associate in the Department of Internal Medicine, made use of data from a new technology called high throughput RNA sequencing to analyze more than 120 million RNA sequences from human cerebellum. Using this data, the team was able to quantify how often Alu-derived exons were included in the mature RNA sequences, which provide the final blueprint for protein production, and where they were inserted in the genes.
"What we found is that these exons tend to avoid protein-coding regions of the genes and rather they end up in the non-coding region that precedes the protein-coding region, called the five prime untranslated region or 5' UTR," Xing explained. "This is the part of the gene that usually contains regions that help control the stability of the messenger RNA and the efficiency at which the messenger RNA is translated into protein."
Experiments to probe the function of these newly inserted elements proved that Alu exons in this region are able to alter the efficiency of messenger RNA translation, which means they affect how fast protein is produced from the altered genes.
The study also suggests that the effect of the newly created exons might be amplifi
|Contact: Jennifer Brown|
University of Iowa Health Care