HIV gag stem loop 3 (GSL3) is a secondary structural component of the Retroviral Psi packaging element, also known as the psi recognition element. This domain plays a major role in RNA packaging and is located the 5’ untranslated region of the unspliced HIV-1 genome. GSL3 is known to direct specific packaging of HIV-1 genomic RNA. While deletion of GSL3 leads to decreases in both viral RNA packaging and dimerization, mutagenic studies have shown that it does not eliminate encapsulation of retroviral RNA.

Pharmaceutical Advancements

Interaction with NCp7

RNA encapsulation involves detection of the psi recognition element by the protein NCp7. NCp7 contains two successive

zinc finger A zinc finger is a small protein structural motif that is characterized by the coordination of one or more zinc ions (Zn2+) in order to stabilize the fold. It was originally coined to describe the finger-like appearance of a hypothesized struct ...

s which are linked by a stretch of basic residues. Their function is to activate annealing of primer

tRNA Transfer RNA (abbreviated tRNA and formerly referred to as sRNA, for soluble RNA) is an adaptor molecule composed of RNA, typically 76 to 90 nucleotides in length (in eukaryotes), that serves as the physical link between the mRNA and the amino ac ...

to the initiation site (where reverse transcription occurs). During this process, GSL3 interacts with NCp7 specifically. Current pharmaceuticals utilized for HIV/AIDS treatment inhibit fundamental processes in the replication cycle of the retrovirus. This interaction is a potential point of inhibition.

Inhibitory Ligands

Inhibitor development remains in an early phase. The challenge of synthesizing a compound with a simple molecular structure and low molecular weight in order to limit side interactions and the existence potentially detrimental stereoisomers requires both a computational and high-throughput approach. 2-((5-nitroquinolin-8-yl)thio)ethanol, a potential

lead compound A lead compound (, i.e. a "leading" compound, not to be confused with various compounds of the metallic element lead) in drug discovery is a chemical compound that has pharmacological or biological activity likely to be therapeutically useful, b ...

, is shown at right. It is selective for the loop structure of GSL3 over double and single stranded RNA. This implies that if released in a cell targeted by HIV, it would block the stem-loop and thus limit productive interaction with NCp7.

References

{{Reflist Cis-regulatory RNA elements