Find a hybrid DNA-RNA virus

2012/05/03 Etxebeste Aduriz, Egoitz - Elhuyar Zientzia Iturria: Elhuyar aldizkaria

• Mikrobiologia

In a hot spring in Lassen National Volcanic Park, California, the genome of a virus appears to be formed by the recombination of an RNA virus and a DNA virus. So far it was not known. Researchers at Portland State University have unveiled the discovery in the journal Biology Direct.

The researchers conducted a metagenomic study of the thousands of viral sequences of a sample of Lake Boiling Spring, with the surprise of finding a DNA sequence that coded a protein that until now had only seen in RNA viruses. They have formed the entire genome of the virus and have seen that the RNA virus sequence is next to that of another protein exclusive to DNA viruses. The new virus, called BSL RDHV (Boiling Spring Lake DNA-RNA hybrid virus).

The researchers conclude that this is a hybrid created by the recombination of two very different viruses. But they don't know how the RNA virus sequence passed from RNA to DNA, as these RNA viruses don't have the reverse transcriptase enzyme needed to perform this conversion. According to the researchers, one option is that an RNA virus, a DNA virus and a retrovirus can simultaneously infect the same cell, that the reverse transcriptase of the retrovirus makes a DNA copy of this RNA virus sequence and that such copy is incorporated into the DNA genome. In any case, it is surprising for researchers that these two types of evolutionarily far away viruses can be recombined.