* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download 22(L)/S/O - India Environment Portal
Cell-penetrating peptide wikipedia , lookup
Biochemistry wikipedia , lookup
Genetic code wikipedia , lookup
Messenger RNA wikipedia , lookup
X-inactivation wikipedia , lookup
Gene regulatory network wikipedia , lookup
Artificial gene synthesis wikipedia , lookup
Non-coding DNA wikipedia , lookup
Promoter (genetics) wikipedia , lookup
Molecular evolution wikipedia , lookup
List of types of proteins wikipedia , lookup
Transcriptional regulation wikipedia , lookup
Polyadenylation wikipedia , lookup
RNA polymerase II holoenzyme wikipedia , lookup
Vectors in gene therapy wikipedia , lookup
Eukaryotic transcription wikipedia , lookup
Silencer (genetics) wikipedia , lookup
Nucleic acid analogue wikipedia , lookup
Epitranscriptome wikipedia , lookup
Deoxyribozyme wikipedia , lookup
Gene expression wikipedia , lookup
RNA interference wikipedia , lookup
Non-coding RNA wikipedia , lookup
22(L)/S/O/ The Times of India/ New Delhi/ 02/ 11/ 07 RNA A Brave New World Scientists across the world are waking up to the power of ribonucleic acid, which may be the catalyst in the quest for cures of dreaded diseases likes AIDS, cancer and even common colds. Subodh Verma investigates Asilent revolution sweeping through the obscure world of molecular biology could be the beginning of finding cures for some of the most dreaded diseases like AIDS, cancer, hepatitis and even common colds. Scientists working in dozens of research labs across the world, including in India, have discovered that RNA (ribonucleic acid), long thought of as an important but lowly ‘messenger’ in the complex biochemical factory called the cell, is actually a manager and regulator with wide-ranging powers. Philip Sharp, who got the Nobel Prize for medicine in 1993, says that these discoveries are “the major breakthrough of the last decade and perhaps of several decades”. Indian scientists have been involved in this cutting edge research. A Hyderabad based husband-wife duo - Utpal Bhadra of the Centre for Cellular & Molecular Biology and Manika Bhadra of Indian Institute of Chemical Technology – were among the first to discover gene silencing by RNA interference. The 2006 Nobel Prize was awarded to two American scientists for this discovery. Sunil Mukherjee of International Centre for Genetic Engineering & Biology at Delhi is working on manipulation of genes in plant cells and in developing virus resistant crops. For over half a century it was believed that RNA merely carries the blueprint of proteins from DNA to ribosomes and helps in assembling the desired protein molecules. Recent discoveries have substantially changed, if not overturned, this belief. Now it has been found that besides doing this, RNA molecules regulate many important processes, including shutting off the blue-print carrying genes themselves. DNA carries the genetic code in the form of precise sequence of four chemical units (A, T, G and C). Each DNA molecule contains millions of these units. Some specific sequences are used for making proteins – these are called genes. The rest of the DNA was considered junk, leftover from millions of years of evolution. One of the crucial discoveries is that even these non-coding portions of the DNA are used to create small or micro RNA molecules. Ronald Breaker, of Yale University says, “The recent discoveries of non-coding RNA functions, such as microRNAs and riboswtiches, are remarkable because they reveal a far greater role for RNA in cells”. There are hundreds of RNA molecules floating around in the cell, performing a variety of functions. They regulate what combines with what, they switch processes on and off, and they control rates of reaction. According to Sidney Altmann, winner of the chemistry Nobel Prize in 1989, the main task of scientists in the immediate future will be to find out what all these hundreds of types of RNA are doing in the cell. Some of the activities of RNA have been deciphered. One of them is called RNA interference (RNAi). It has been found that introducing a double strand RNA (dsRNA) into a cell sets of a chain of events resulting in the destruction of messenger RNA. This effectively ‘silences’ the gene, which was sending out the messenger. RNAi has immense possibilities. It is based on a naturally occurring process and it is very precise. Using it, one can silence any gene and thereby stop protein production related to that gene. So, it can be deployed to kill off viruses, or bacteria. It can provide a potent tool of silencing rogue genes, say, those causing cancer. RNAi is also being used to selectively switch off genes to observe what happens to the body. Scientists had been tweaking genes through more difficult means till now – introducing bits of DNA into cells to change the genetic code. This was easy in plants which have less complicated structures. So, genetically modified (GM) crops developed. But the RNAi method can be used much more effectively and in animal cells too. Research indicates that small RNA is involved in other crucial tasks too. According to Peter Seeburg of the Max-Planck Institute, Heidelburg, they play a role in regulating organ specification, that is, development of different organs, and also in running the body’s immune system. However, all experts agree that it’s early days yet. One of the major issues scientists are grappling with is: how to deliver the suitable short interfering RNA at the precise place where it will perform its function. Claes Wahlestedt of the Scripps Research Institute, Florida says that, “delivery (is) a hurdle that nobody has been able to overcome, other than in very small incremental advances.” Utpal and Manika Bhadra have found that RNA plays a key role when cells divide rapidly, as in cancerous cells. This could lead to a method for controlling cancer. They have also developed nano-tubes for delivering the required small RNA. “At this point we have only explored the tip of the RNA iceberg and most still lies below the surface,” says Stephen Holbrook of the Lawrence Berkeley Laboratory. However, international cooperation between scientists, using new IT tools to scan and catalogue molecules is driving research at a furious pace. So much so that commercialization of RNA based medicines is already on the horizon. The New Pharma Jackpot? Within a decade and a half, what was a mere twinkle in the eyes of scientists has turned into a multi billion dollar flood. But that is because one of the cornerstones of genetic science got upturned. Scientists in public funded universities and research institutions spread across Europe, North America, and even India carried out the basic research. As the momentum gathered, and Nobel Prizes started flowing in, the focus began to turn to applications. This was understandable: with the rising trend of metabolic disorders like diabetes, heart diseases, arthritis, cancer in the West, and also the widening sweep of unconquered diseases like AIDS, there was a growing panic both in the public at large and among pharmaceutical manufacturers. Few drugs were coming out of the research pipeline. Discoveries about RNA’s key regulatory role held out hopes for breakthroughs. First, many of the scientists themselves set up firms to commercialise the nascent discoveries. Thus, Nobel laureate Philip Sharp of MIT set up Alnylam, while another group of scientists led by Stephen Fodor launched Affymetrix. These start-ups are making tools for research based on bio-informatics or actively researching delivery mechanisms for RNA-based therapies. Meanwhile, big pharmaceutical companies moved in with big bucks. In a series of high profile take-overs through 2006 and continuing this year, Merck acquired Sirna Therapeutics Inc, a specialist in RNA interference (RNAi), for $1.1 billion, Pfizer entered into a multi-million dollar deal with Mirus Bio to push research on RNA, AstraZeneca bought MedImmune for $14.6 billion, Novartis purchased NeuTec Pharma for $576 million, and Schering-Plough acquired Organon for $14.3 billion. Drug industry watchers say that big pharma is now raring to grab the burgeoning bio-tech market. From cloistered university labs to the billion dollar limelight – RNA has come a long way. But people will have to wait longer before actual therapies hit the market.