Protein coding `junk genes` key to understanding cancer

Washington – Researchers have found close to one hundred novel human gene regions that code for proteins and a number of these regions are so-called pseudogenes, which may be linked to cancer.

In humans, only about 1.5 percent of the human genome or DNA consists of protein-coding genes. Of the remaining DNA, some sequences are used to regulate the genes’ production of proteins, but the bulk of the DNA is considered to lack any purpose and is often referred to as “junk DNA”.

Within this junk DNA there are so-called called pseudogenes. Pseudogenes have been considered as non-functional genes, which are believed to be gene remnants that lost their function during evolution.

Researchers have now presented a new proteogenomics method, which makes it possible to track down protein coding genes in the remaining 98.5 percent of the genome, something that until now has been an impossible task to pursue. Among other things, the research shows that some pseudogenes produce proteins indicating that they indeed have a function.

Associate Professor and study leader Janne Lehtio’s team found evidence for almost one hundred new protein-coding regions in the human genome.

Similar findings were made in cells from mice. Many of the new proteins encoded by pseudogenes could also be traced in other cancer cell lines, and the next objective on the researchers’ agenda is to investigate if these genes in the “junkyard” of the genome play a role in cancer or other diseases.

Dr Lethio said that their study challenges the old theory that pseudogenes don’t code for proteins, asserting that their method allows for protein based genome annotation in organism with complex genomes and can lead to discovery of many novel protein coding genes, not only in humans but in any species with a known DNA sequence.

The study has been published in the scientific journal Nature Methods.