RNA challenges cancer....In laboratories around the world, researchers are taking a fresh look at RNA RNA: see nucleic acid.
in full ribonucleic acid
One of the two main types of nucleic acid (the other being DNA), which functions in cellular protein synthesis in all living cells and replaces DNA as the carrier of genetic , a nucleic acid nucleic acid, any of a group of organic substances found in the chromosomes of living cells and viruses that play a central role in the storage and replication of hereditary information and in the expression of this information through protein synthesis. made from a single strand of chemical components called nucleotides. Cells normally use the nucleotide sequences of RNA strands to transfer the protein-building instructions from double-stranded DNA DNA: see nucleic acid.
or deoxyribonucleic acid
One of two types of nucleic acid (the other is RNA); a complex organic compound found in all living cells and many viruses. It is the chemical substance of genes. to ribosomes Ribosomes
Small particles, present in large numbers in every living cell, whose function is to convert stored genetic information into protein molecules. , sites inside cells where proteins are made.
Some investigators contend that RNA can do much more than simply carry DNA's message. For example, one research group has devised a form of gene therapy using ribozymes, enzymes made of RNA, to correct faulty protein-making blueprints (SN: 6/8/96, p. 357).
Another group suggests that ribozymes can eliminate harmful proteins after they're made. Joachim W. Engels of the University of Johann Wolfgang Goethe in Frankfurt, Germany, and his colleagues report that they have designed ribozymes that bind to and break apart a mutant protein that turns cells cancerous.
The protein, part of the signaling machinery that governs cell growth, is encoded by a gene called N-ras. A cell has two copies of the gene, but a mutation in just one copy causes the cell to proliferate pro·lif·er·ate
To grow or multiply by rapidly producing new tissue, parts, cells, or offspring. out of control. Engels' group has synthesized RNA strands that, in test-tube studies, destroy the proteins produced by a mutant N-ras gene but spare proteins encoded by the normal version of the gene. To allow the ribozymes to do the same inside cells, the researchers have modified the RNA strands slightly, making them more resistant to degradation by cellular enzymes. They plan to test these ribozymes on tumor cells from a person with an N-ras mutation. "The real proof will be if the proliferation proliferation /pro·lif·er·a·tion/ (pro-lif?er-a´shun) the reproduction or multiplication of similar forms, especially of cells.prolif´erativeprolif´erous
n. disappears," says Engels.