ROANOKE TIMES
Copyright (c) 1996, Roanoke Times
DATE: Sunday, June 23, 1996 TAG: 9606240149
SECTION: NATIONAL/INTERNATIONAL PAGE: A-6 EDITION: METRO
SOURCE: Newsday
By taking an inside-out view of the human immune system, scientists reported last week that they have deciphered a key family of genes involved in disease control, organ rejection and self-destructive diseases such as arthritis and multiple sclerosis.
In ``reading'' the longest stretch of human DNA ever analyzed in complete detail, Dr. Leroy Hood's team at the University of Washington also has given a large boost to the Human Genome Project, the effort to identify and analyze each of the 3 billion pieces of DNA in the human set of genes.
Their stretch of DNA - 684,973 links, or base pairs - contains the first complex multigene family ever completely analyzed, Hood said. It contains 63 genes on chromosome 7 that make so-called T-cell receptors, the ``business end'' of certain white blood cells.
The receptors are a main line of defense against infection. They sit on cell surfaces, like eyes or feelers, and are responsible for identifying dangerous ``foreign'' materials that get into the body.
``Knowing all the information about this family [of genes] lets us interrogate the immune system in new and interesting ways,'' Hood said. ``Ultimately, it will let us develop therapeutic drugs for getting rid of bad T-cells.''
Hood and his colleagues said that studying the T-cell receptors ``has provided new insights into the organization, evolution and diversification of this gene family, as well as the general architecture of the largest stretch of human chromosome analyzed to date.''
Hood's co-workers are Lee Rowen, at the University of Washington, and Ben Koop, his former student, now at the University of Victoria, Canada. Their research was reported Friday in the journal Science.
The achievement ``is tremendously important for the scientists studying these things,'' said immunologist Philippa Marrack, at the Howard Hughes Medical Institute and the National Jewish Center, in Denver. ``It basically gives us the hardware from which you decide what to do next. It's an unbelievably large amount of information.''
One goal, she said, is to understand whether these immune system genes ``have anything to do with the inheritance of autoimmune diseases,'' such as multiple sclerosis.
The researchers also found, among the human T-cell genes, that one piece of DNA has been copied and moved from chromosome 7 to chromosome 9. ``Thus, we have evidence for a mechanism giving rise to new, but related, gene families,'' Hood said.
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