PARIS — Scientists in the United States have decoded the overall structure of the HIV virus genome that causes AIDS in humans, according to a study published Thursday.
The breakthrough should help develop strategies for combating the virus with new anti-viral drugs, the researchers said.
“We are beginning to understand tricks the genome uses to help the virus escape detection by the human host,” said Kevin Weeks, a professor at the University of North Carolina at Chapel Hill and the study’s main architect.
Like the viruses that cause influenza and hepatitis C, HIV carries its genetic information in single-strand RNA rather than the double strand DNA found in all living organisms and certain viruses.
This make is more difficult to decode because, unlike DNA, RNA is able to fold itself into intricate, three-dimensional patterns.
Earlier studies have succeeded in modeling small regions of the HIV genome, which consists of two strands each containing nearly 10,000 nucleotides, the basic molecular building blocks of both DNA and RNA.
Using a new technique, Weeks and colleagues produced images which, while lower in resolution, spanned a much larger area.
The study, published in the British journal Nature, should help scientists discover ways in which the RNA genome determines the lifecycle of the HIV virus.
“One approach is to change the RNA sequence and see if the virus notices,” said Ronald Swanstrom, a microbiologist at UNC and a co-author of the study.
“If it doesn’t grow as well when you disrupt the virus with mutations, then you know you’ve mutated or affected something that was important to the virus,” he said in a statement.
Hashim Al-Hashimi of the University of Michigan, also writing in Nature, said in a commentary that the study was a “considerable achievement” in so far as it provided an “aerial view” of the genome’s overall structure.
“Structural biologists can now use this genomic map to judiciously zoom in on pieces of the HIV-1 genome and determine architectural and functional principles at the atomic level,” he said.
AIDS first came to public notice in 1981, when alert US doctors noted an unusual cluster of deaths among young homosexuals in California and New York.
It has since killed at least 25 million people, and 33 million others are living with the disease or the HIV virus, which destroys immune cells and exposes the body to opportunistic disease.
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