Study reveals genetic activity of key step in malaria parasi...( In a finding that could significantly e...)

The study, scheduled for publication on-line in the preview edition of Public Library of Science Biology (PLoS Biology) on August 20, reveals that an unusually high percentage of genes at least 60 percent -- were "turned on," or expressed, at the third and critical stage in the parasite's life cycle when it invades red blood cells and wreaks the havoc that causes the disease's symptoms.

Moreover, the analysis showed that the pattern, or timing, of gene expression was unique, with most genes expressed only once during the stage, and in a certain order, for a simple, continuous cascade of gene expression, beginning with genes that correspond to normal cellular processes and ending with highly specialized functions for invading red blood cells. The order and timing of expression resembled a molecular "just in time" factory, whereby cellular components are created only as part of a precisely timed process, rather than on demand.

The discovery of the pronounced level of activity, in which a gene is transcribed into messenger RNA on the path toward producing a protein, points to numerous new potential targets for drug and vaccine therapy. And the timing of expression of individual genes offers insights into the functions of the proteins they encode.

In addition, the revelation that the genes were expressed in a relatively rigid pattern suggests a possible vulnerability in the organism's manufacturing process. Normally, unicellular organisms that cause disease, such as bacteria and parasites, are dynamic entities capable of shifting their patterns of gene expression in response to environmental conditions. But the expression pattern seen in Plasmodium
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Contact: Jennifer O'Brien
jobrien@pubaff.ucsf.edu
415-476-2557
University of California - San Francisco
11-Aug-2003