HIV genome bends over backwards to help virus take over cells
The virus HIV-1 has a tiny genome. All of its nine genes fit on one single RNA molecule, and the organism’s entire library of genetic material consists of only 10 kilobases (for context, the human genome is around 3 million kilobases). But despite the virus’ small pool of genes, it is able to use a method called alternative splicing to produce many various proteins with different purposes. The RNA transcripts for these proteins are like individual words hidden in a wall of text, says Whitehead Institute Fellow Silvi Rouskin: “You cut and paste them [through alternative splicing], and then when you put them all together you have a sentence that makes sense.” Since none of the HIV’s genes even encode the cellular machinery needed to “cut and paste” RNA — it hijacks its host’s materials for that — scientists are still working out exactly how every HIV molecule is able to...