The p65 protein not only brings two parts of the RNA closer together to allow for the attachment of the TERT protein, but it also folds around the end of the RNA strands to protect them before the telomerase assembles. Without its protein shield, the "naked" RNA is susceptible to degradation and could be chewed up by other enzymes, Singh said.
The p65 protein belongs to a family of "La-motif" proteins, molecules that act as "RNA chaperones" in many organisms including humans, said Feigon.
"How the p65 protein binds with RNA has never been clear," Feigon said. "Nobody could figure it out, and that's partly because they were missing a critical, extra part of the protein which changes from being a completely random coil to being folded and ordered when it interacts with RNA."
Studying p65 within the humble Tetrahymena may help Singh and Feigon better understand its La-motif cousins within the human body, which may also sport protein tails.
"A lot of data indicates that the protein tail is important for the binding of all kinds of RNAs in human cells," Feigon said. "It is particularly critical for the translation of the hepatitis C viral RNA. Now we can potentially predict how those proteins will assemble and interact with their RNAs."
The researchers who first discovered telomerase were awarded the Nobel Prize in 2009. They also used Tetrahymena thermophila, a tiny microorganism with hair-like flagella commonly found in fresh water.
|Contact: Stuart Wolpert|
University of California - Los Angeles