Scientists discover small RNAs that regulate gene expression and protect ...( RNA is best known as a working copy ...)

RNA is best known as a working copy of the DNA sequence of genes. In this role, its a carrier of the genes instructions to the cell, which manufactures proteins according to information in the RNA molecule.

But molecular biologists have increasingly realized that many RNA snippets -- so-called small RNAs -- also directly influence which genes make proteins, and in some cases, how much protein. Theyve also found that some small RNAs play a unique role in protecting the integrity of genetic material.

Scientists at Cold Spring Harbor Laboratory (CSHL) have played a central role in these discoveries since the beginning of the decade. In recent weeks they have published additional findings adding to our knowledge of small RNAs, identifying a brand new class and clarifying how a known class acts to regulate gene activity.

It turns out that there are more types of small RNA molecules than anyone initially suspected, said Gregory J. Hannon, Ph.D., CSHL professor and pioneer in small RNA research. And we are finding that each type that we discover acts in more ways than had previously been appreciated.

RNA molecules consist of sequences of chemical units, or bases, that are copies of the DNA sequence. Each specific sequence can recognize related sequences in other RNA or DNA molecules. To regulate cellular activities, small RNA snippets, each containing 20 to 30 bases, join with special protein helpers to eliminate or modify target molecules. But of the billions of bases in a cells DNA, what determines which RNA snippets are chosen for this role"

Dr. Hannon and his collaborators are harnessing highly efficient new machines that determine the sequence of bases in millions of small RNA molecules simultaneously. They then scan the known genome to find matching sequences, as well as the sequences nearby. This original context is crucial to understanding why some snippets are chosen as re
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