Aug. 5 (HealthDay News) -- U.S. scientists have decoded the structure of an entire HIV genome, a breakthrough which could improve understanding of how the virus infects humans and could lead to the development of new antiviral drugs.

Like viruses that cause influenza, hepatitis C and polio, HIV carries its genetic information as single-stranded RNA rather than double-stranded DNA. Information encoded in RNA is more complex.

The HIV RNA genome is huge, composed of two strands of almost 10,000 nucleotides each. Previously, scientists had managed to model only small regions of the HIV RNA genome.

In this study, University of North Carolina at Chapel Hill researchers used specially developed technology to analyze the architecture of HIV genomes. They found that the RNA structures influence multiple steps in HIV's infection cycle.

"There is so much structure in the HIV RNA genome that it almost certainly plays a previously unappreciated role in the expression of the genetic code," study leader Kevin Weeks, a professor of chemistry, said in a news release.

He and his colleagues said the findings would help unlock additional roles of RNA genomes that are important to the life cycle of HIV and other viruses.

"One approach is to change the RNA sequence and see if the virus notices," co-author Ron Swanstrom, a professor of microbiology and immunology, said in the release. "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."

The study appears in the Aug. 6 issue of the journal Nature.

SOURCE: University of North Carolina at Chapel Hill School of Medicine, news release, Aug. 5, 2009