Cold Spring Harbor, N.Y. The nucleus of a cell, which houses the cell's DNA, is also home to many structures that are not bound by a membrane but nevertheless exist as distinct compartments. A team of Cold Spring Harbor Laboratory (CSHL) scientists has discovered that the formation of one of these nuclear subcompartments, called paraspeckles, is triggered by a pair of RNA molecules, which also maintain its structural integrity.
As reported in a study published online ahead of print on December 19 in Nature Cell Biology, the scientists discovered this unique structure-building role for the RNAs by keeping a close watch on them from the moment they come into existence within a cell's nucleus. The scientists' visual surveillance revealed that when the genes for these RNAs are switched on, and the RNAs are made, they recruit other RNA and protein components and serve as a scaffolding platform upon which these components assemble to form paraspeckles.
The two RNAs described in the study, named MENε and MENβ, are "non-coding" RNAs a type of RNA that does not serve as a code or template for the synthesis of cellular proteins. The genes that give rise to these non-coding RNAs are now thought to make up most of the human genome, in contrast to the genes that produce protein-coding RNAs, which account for approximately 2% of the human genome.
"We've known for several years that much of the other 98% of the genome doesn't encode for useless RNA," explains CSHL's Professor David L. Spector, who led the current study. "Various types of non-coding RNAs have been found that regulate the activity of protein-coding genes and cellular physiology in different ways. Our results reveal a new and intriguing function for a non-coding RNAthe ability to trigger the assembly and maintenance of a nuclear body."
The nuclear bodies in questionthe paraspecklesare believed to serve as nuclear storage depots for RNAs that are ready to be
|Contact: Hema Bashyam|
Cold Spring Harbor Laboratory