The Promise and Power of RNA

Pharmaceutical companies are focusing more on RNA than the "protein-making genes." Recent scientific discoveries show that RNA has more of an impact on the actual protein than a gene that can code for many proteins (as we learned in class). When the strand of DNA transcribed a strand of RNA, the RNA has some control over the protein that is created.

“This is potentially the biggest change in our understanding of biology since the discovery of the double helix,” said John S. Mattick, a professor of molecular biology at the University of Queensland in Australia.

Pharmaceutical companies have developed a drug called RNA Interface, or RNAi. They are creating drugs that are stop the production of a protein, instead of trying to repair the damage caused by a protein that was already produced.

The two scientists credited with discovering the basic mechanism of RNA interference won the Nobel Prize in Physiology or Medicine in 2006, only eight years after publishing their seminal paper. And three scientists credited with discovering the closely related micro-RNA in the 1990s won Lasker Awards for medical research this year.

Research is focusing on micro-RNA, short strands of interference RNA that can reduce protein production. So far, more than 400 strands of micro-RNA's have been found. Since each strand has the possibility to affect hundreds of genes, "the activity of more than half the genes in the human genome is affected by micro-RNA," according to David P. Bartel, a biologist at the Whitehead Institute in Cambridge, Mass., and at the Massachusetts Institute of Technology.Scientists have discovered that micro-RNA's contribute to the formation of some cancers, the ability to block cancer, and the proper function of the heart and blood cells.

Other types of RNA have also been discovered, including small interfering RNA (siRNA), piwi-interacting RNAs (piRNA), chimeric RNA, and promoter-associated and termini- associated long and short RNAs. PRe-existing RNA include messenger RNA (mRNA), transfer RNA (tRNA), and small nucleolar RNA (snoRNA), which all play roles in protein production. Although scientists do not understand what each type of RNA does, they allow for a lot of future options to cure and treat protein related diseases. Not is the function of the RNA types unknown, scientists also disagree about their actual function. Some believe that RNA has the ability to turn on and off genes, while other scientists think that RNA can only fine tune the genes and increase or decrease the prominence.

All of the new discoveries are “revealing a level of regulation and complexity that I don’t think the current organizational model of the genome ever envisioned,” said Thomas R. Gingeras, professor and head of functional genomics at Cold Spring Harbor Laboratory.

Currently, scientists are focusing on interference RNA. While in theory it is easy to understand how interfering RNA could silence a gene, there is no convincing data that it will work in humans. There is also the fear that the RNA could might silence genes beyond its intended target, which would cause unwanted effects. Scientists plan to use double-stranded RNA, however, it does not actually occur in the human body. When trying to get into a cell, it sets off an immunoresponse because the body recognizes the double stranded RNA to be a virus. Also, most cell membranes are negatively charged, as is the RNA. So, the RNA would never hit the cell. Many startup pharmaceutical companies are researching entry methods.

Another pitfall of RNA interference is that it only turns genes off and cannot stimulate the cell to increase protein levels. However, it was discovered that RNA activation can. RNAa can cause a gene to become more active and enhances the activity of proteins to bind to the gene promoters.

While no treatments have been created as of yet, there is research being done on this new potential treatment to many disease.



http://www.nytimes.com/2008/11/11/science/11rna.html?partner=permalink&exprod=permalink