RNA revelations – Science Spot

Stanford University’s Roger Kornberg is the sole winner of this year’s Nobel Prize for Chemistry for figuring out exactly how the genetic material, DNA, in a eukaryotic organism, such as a mouse, a human, or a yeast is transcribed into RNA, which then provides the instructions to the cell machinery for making proteins.

In order for organisms with a well-defined nucleus within their cells, eukaryotes, to transfer their genes from the cell nucleus to the site of protein production, a transcription process must take place. This makes a facsimile of the genes held by DNA, converts them into messenger RNA and then transfers this to the outer parts of the cell. If transcription fails an organism quickly dies, as happens should you ingest of the death cap toadstool, which is rich in toxins that block transcription.

Kornberg (Photo: Stanford)

Merely disturbing transcription can have devastating effects too and underlies numerous human illnesses such as cancer, heart disease and certain forms of inflammation. Understanding transcription is therefore key to understanding these diseases. Kornberg’s work can also be used by stem cell researchers hoping to control transcription and expression of proteins which occur as stem cells differentiate into different cell types, whether neurones, muscle, or heart cells.

Forty-seven years ago, Kornberg’s father Arthur Kornberg won the Nobel Prize in Physiology or Medicine for his pioneering work on how genetic information is transferred from one DNA molecule to another. What Kornberg junior has done is to explain how genetic information is transferred from DNA to messenger RNA (mRNA), which carries the coding information out of the cell nucleus for protein construction.

Kornberg’s view of transcription. DNA double helix is in blue, RNA polymerase enzyme in white, and the growing RNA strand in red (Credit: Kornberg et al, 2001)

Crystallographic work by Kornberg’s team culminated in detailed atom-by-atom pictures depicting the working transcription apparatus. Like a molecular-scale film sequence, Kornberg’s structures show how the lead player, the RNA-strand gradually develops, and how it is supported by other molecules.

A theme ran through the Chemistry and the Medicine prizes this year with Medicine awarded jointly to another Stanford researcher Andrew Fire and to Craig Mello of the University of Massachusetts for their work on RNA interference and gene silencing by double-stranded RNA.

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