- Person
- Roger Kornberg
- Lived
- b. 1947
- Field
- Structural biology
- From
- American
The story
Every human cell contains about two metres of DNA, folded into a nucleus a few thousandths of a millimetre wide. For a century scientists knew that chromosomal DNA was bound to roughly equal amounts of proteins called histones, but no one understood how. Histones seemed so sticky and variable that many researchers dismissed them as shapeless glue.
Roger Kornberg, the son of Jewish biochemists Arthur and Sylvy Kornberg, took up the problem in 1972 as a young researcher at the Medical Research Council Laboratory of Molecular Biology in Cambridge, England, though his mentor Aaron Klug warned him it was messy. Kornberg spotted a neglected paper in which histones extracted by gentle methods separated cleanly into pairs. Working with Jean Thomas, he showed that two histones, H3 and H4, join in an exact four-part unit. From this he reasoned that chromatin must be built from repeating particles, each containing two copies each of four histones with about 200 base pairs of DNA wrapped around the outside.
He then remembered experiments in which an enzyme cut chromosomal DNA into pieces of a regular size. Searching the library, he found a report that measured the unit at 205 base pairs, almost exactly his prediction. His 1974 papers in Science described the structure now called the nucleosome. Later electron microscopy and, in 1997, an X-ray crystal structure by other scientists confirmed it in atomic detail.
The nucleosome turned out to be far more than packaging. Kornberg and his partner Yahli Lorch showed in 1987 that nucleosomes block genes from being switched on, and researchers have since found that chemical tags added to and removed from histones help control which genes are active in each cell. This field, epigenetics, is now one of the busiest areas of biology and medicine, and drugs that target the enzymes that add or remove histone tags are used in treating some cancers. Kornberg went on to receive the 2006 Nobel Prize in Chemistry for related work on how genes are read.
Why it matters
The nucleosome is the foundation of epigenetics, the study of how genes are switched on and off, which is guiding new research and treatments for cancer and other diseases.
About Roger Kornberg
Stanford biologist who discovered how DNA is packaged in our cells and made the first atom-by-atom pictures of genes being read, knowledge used in cancer and stem-cell research. Nobel Prize 2006.
More about Roger Kornberg
Sources
- Roger D. Kornberg, Biographical NobelPrize.org
- Roger D. Kornberg Wikipedia
- Roger Kornberg Jewish Virtual Library
Another act of tikkun olam. This is part of tikkun olam, the Jewish idea of repairing the world, and every one of us can add to it.