While in humans such eviction of nucleosomes is specific to only some sections of the DNA strand and performed only when needed, in Plasmodium the situation is vastly different.
Le Roch's experiments in the lab show that 18 hours after Plasmodium enters a red blood cell, a huge eviction of nucleosomes occurs in the Plasmodium DNA. Gene transcription throughout the genome follows; after multiplication into up to 32 daughter cells, the newly-formed parasites are ready to exit the red blood cell and invade new ones about 18 hours later.
"We found in our experiments that histones are massively evicted everywhere in the Plasmodium genome, resulting in most of the Plasmodium genes to be transcribed at once," Le Roch said. "If we can find a candidate enzyme that can regulate this massive histone eviction, we could halt or greatly limit Plasmodium replication."
Study results appear this month in the journal Genome Research.
"Dr. Le Roch's findings document a global mechanism mediating significant changes in gene expression as the parasites transition through developmental stages in the human hosts," said Anthony A. James, a distinguished professor of microbiology & molecular genetics and molecular biology & biochemistry at UC Irvine, who was not involved in the research. "As well as being a major basic discovery, this provides a basis for probing the mechanisms for novel drug development."
|Contact: Iqbal Pittalwala|
University of California - Riverside