PROVIDENCE, R.I. -- Scientists have provided direct evidence that a class of proteins plays a role in extending life.

Their study, published in this week's issue of the journal Nature, demonstrates that a brief genetic response to heat stress can increase a fruit fly's life span at normal temperatures. The finding uncovers a potential mechanism for aging because the capacity to moderate stress is a central function to regulating that aging mechanism.

In the study, Marc Tatar and colleagues from the University of Minnesota exposed fly strains to short doses of nonlethal warmth, inducing expression of a protein dubbed hsp70. Flies bred to contain extra copies of hsp70 genes responded to the warmth by producing a lot of hsp70, which substantially increased their life span over a two-week period after heat treatment.

Only a brief, low level of genetic expression was required to obtain a long-term improvement in survival of the flies, said Tatar, now an assistant professor of ecology and evolutionary biology at Brown University.

Hsp70 is one of the body's many "chaperone" proteins, which promote the proper folding and shaping of other proteins during biological processes. Molecular chaperones, such as hsp70 or "heat-shock proteins," are thought to combat stress-related damage to protein function caused by exposure to heat or cold.

The researchers think fruit flies produce hsp70 after exposure to warmth, because it may re-establish other proteins adversely affected by warming. Hsp70 may also interact with other stress response mechanisms.

Transient but effective levels of hsp70 could be present when stress is routinely encountered, the researchers said. Hsp70 may repair and restore higher-order cell functions, which themselves would otherwise quicken the mechanism responsible for aging.

However, people shouldn't think they will live longer by taking daily doses of heat or by sitting in endless saunas, Tata
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Contact: Scott Turner
Scott_Turner@Brown.edu
(401) 863-2476
Brown University
6-Nov-1997