Difficult breathing. mouse in this breathing room will probably get asthma after inhaling methacholine, which induces the disease in this strain of the subject asthma.
While asthma attacks are triggered by a series of environmental factors - mold for animals dusty teddy - the disease itself runs in families, which leads the researchers asthma in search of the genes responsible. Now researchers have found a set of genes that confer asthma susceptibility in mice.
Scientists already had their eyes on a region of human chromosome 5, called 5q23-35, where they suspect that a number of asthma-related genes reside: Many asthmatics have genetic mutations in this part of the chromosome. Several candidate genes controlling immune responses associated with asthma, but researchers do not know which genes make people more likely to come down with asthma in the first place.
To determine which candidate genes are responsible for asthma susceptibility, immunologist Rosemarie DeKruyff and colleagues at Stanford University in Palo Alto, California, sought to restrict 5q23-35 to a size manageable. They created two mouse strains that were genetically identical except in the region corresponding to 5q23-35 in humans: A strain had mutations that confer susceptibility to asthma and the other strain lacked these mutations. Then consider combinations of these mutations and identify which are most closely linked to asthma, they raised mice and had offspring inhale methacholine, which can trigger asthma. In this way, the researchers learned that the mice had inherited a genetic predisposition to the disease
After many reproductive cycles and tests, the stretch of chromosome that both mouse strains n did not share -. And conferred asthma susceptibility - was 0 times shorter than 5q23-35, the group reports in the December issue of Nature Immunology . There DeKruyff team identified two candidate genes Tim-1 and Tim-3 . Because mice of the subject asthma had multiple mutations in both genes, researchers could not determine whether the one, the other, or both cause asthma. mouse immune cells bearing the variety "sensitive" of Tim-1 , a new gene in search of asthma, have produced the same molecules as bent during an asthma attack. The other gene, Tim-3 , is already known to have a role in the immune system unrelated asset asthma attacks, but because many of the sick mice had mutations in Tim-3 , the researchers say they could not exclude the sensitivity until they can test it outside of Tim-1 .
The work "would be quite significant" if it holds up in humans, says immunologist Marsha Wills-Karp Medical Center Children's Hospital of Cincinnati, Ohio. The most appearance critical of Tim newly discovered genes is that they can cause not only asthma, but other diseases of the immune system as well.
Sites Related
laboratory page author Dale Umetsu
Stanford Center for asthma and allergic disease
About asthma American Lung Association
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