Mutations in the TAR hairpin affect the equilibrium between alternative conformations of the HIV-1 leader RNA

AUTOR(ES)

Huthoff, Hendrik

FONTE

Oxford University Press

RESUMO

The HIV-1 untranslated leader RNA can adopt two mutually exclusive conformations that represent alternative secondary structures. This leader RNA can fold either an extended duplex through long-distance base pairing or a branched conformation in which the RNA locally folds into hairpin structures. Both leader RNA conformations have the TAR hairpin in common, which forms the extreme 5′ end of all HIV-1 transcripts. We report that truncation of the TAR hairpin shifts the equilibrium between the two RNA conformations away from the thermodynamically favored long-distance interaction. However, the equilibrium is partially restored in response to the cations Na+ and Mg2+. The transcripts with mutant TAR structures allowed us to investigate conditions affecting the competition between the alternative conformations of the HIV-1 leader RNA. We also demonstrate that the change in conformation of the leader RNA due to TAR truncations severely affects formation of the HIV-1 RNA dimer.

Documentos Relacionados

• Evolution of a disrupted TAR RNA hairpin structure in the HIV-1 virus.
• Optimal Tat-mediated activation of the HIV-1 LTR promoter requires a full-length TAR RNA hairpin.
• Probing alternative foldings of the HIV-1 leader RNA by antisense oligonucleotide scanning arrays
• The bulge region of HIV-1 TAR RNA binds metal ions in solution
• Identification of a novel HIV-1 TAR RNA bulge binding protein.