Scientists at CSHL uncover new RNA processing mechanism and a new class of ...( A very small fraction of our genetic...),Health

A very small fraction of our genetic material--about 2%-- performs the crucial task scientists once thought was the sole purpose of the genome: to serve as a blueprint for the production of proteins, the molecules that make cells work and sustain life. This 2% of human DNA is converted into intermediary molecules called RNAs, which in turn carry instructions within cells for protein manufacture.

And what of the other 98% of the genome? It has been assumed by many to be genetic junk, a massive accumulation of "code" that evolution has rendered superfluous. Now, however, scientists are discovering that the vast bulk of the DNA in our genomes, while it does not "code" for the specific RNA molecules that serve as templates for protein synthesis, do nevertheless perform various kinds of work. But what types of work, involving what kinds of cellular mechanisms? Given its relative abundance, non-coding DNA and RNA present inviting targets for experimentation.

For years, a laboratory at Cold Spring Harbor Laboratory (CSHL) led by Professor David L. Spector, Ph.D., has studied events within the cell nucleus, where the genetic material is contained. In the November 26th issue of Cell, Spector and a team led by graduate student Jeremy Wilusz report their discovery of a previously unknown mechanism in the nucleus that processes non-coding RNA molecules.

Spector and colleagues discovered the mechanism while examining a non-coding RNA molecule called MALAT1. Resident in the cell nucleus, MALAT1 was observed to split into two parts, one long and one very shortthe latter qualifying as a species of RNA that scientists call small RNAs. The small RNA segment was observed to migrate out of the nucleus into the cell's aqueous cytoplasm. The longer remnant of MALAT1 remained in the nucleus, accumulating in distinct zones called nuclear speckles.

Although it is not yet clear what these processed parts of the original MALAT1 molecule do,
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