gms | German Medical Science

10. Kongress für Infektionskrankheiten und Tropenmedizin (KIT 2010)

Deutsche Gesellschaft für Infektiologie,
Deutsche AIDS-Gesellschaft,
Deutsche Gesellschaft für Tropenmedizin und Internationale Gesundheit,
Paul-Ehrlich-Gesellschaft für Chemotherapie

23.06. - 26.06.2010, Köln

Differences in the frameshift-regulating p1-site in treatment-naïve and PI-resistant HIV isolates

Unterschiede in der Frameshift-regulierenden p1-Region in therapie-naiven und PI-resistenten HIV

Meeting Abstract

  • E. Knops - Universität zu Köln, Institut für Virologie, Köln, Germany
  • G. Théberge-Julien - University of Montreal, Department of Biochemistry, Montreal, Canada
  • R. Kaiser - Universität zu Köln, Institut für Virologie, Köln, Germany
  • D. Hoffmann - University of Duisburg-Essen, Centre for Medical Biotechnology, Essen, Germany
  • L. Brakier-Gingras - University of Montreal, Department of Biochemistry, Montreal, Canada
  • J. Verheyen - Universität zu Köln, Institut für Virologie, Köln, Germany

10. Kongress für Infektionskrankheiten und Tropenmedizin (KIT 2010). Köln, 23.-26.06.2010. Düsseldorf: German Medical Science GMS Publishing House; 2010. DocHIV 07-2

doi: 10.3205/10kit005, urn:nbn:de:0183-10kit0052

Published: June 2, 2010

© 2010 Knops et al.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License ( You are free: to Share – to copy, distribute and transmit the work, provided the original author and source are credited.



Objectives: The HIV replication cycle include a maturation step, in which the viral enzymes are cleaved from the Gag-Pol precursor built due to a frameshift event in p1. Two Gag cleavage-sites (CS) (p7/p1, p1/p6-gag), which were found to be important in PI-resistant HIV, and Pol CS (p7/TFP, TFP/p6-pol) are encoded by a frameshift-regulating site and might contribute to differences in frameshift-efficiencies.

Methods: We analysed the p1 nucleotide sequence of 968 HIV isolates from different patients infected with HIV subtype B of whom 644 patients were treatment-naive and 324 were treatment-experienced patients failing PI therapies. RNA-structure of the p1 hairpin was predicted with m-fold. The frameshift-efficiency was determined with a dual luciferase assay.

Results: Only 21 of 52 nucleotide positions (nt2085-2136) were never subject of sequence variability compared to HxB2 and insertions and deletions were observed. Mutations at five nucleotide positions (ntG2093A, ntA2098G, ntC2108T, ntA2111C, ntC2134T/G) significantly accumulated in PI-resistant HIV. Mainly Gag CS-mutations (G435E, L449F/V) but also non-CS-mutations (S440F, H441Q) were associated with these mutations. Only mutation ntA2098G resulted in CS-mutations in gag (I437V) and pol (05G/05S) reading frame. Interestingly, I437V was correlated with PR mutations (48V, 50V, 54A/V, 82A), whereas 05G only with PR mutation (82A) and 05S with PR mutations (48V, 50V, 54A/V, 82T) in PI-resistant HIV.

The analysis of sequences (n=66) harbouring insertions, deletions, non-CS-mutations (ntC2108T/ntA2111C) and CS-mutations (G435E, 436G/R, I437M, L449P/I/H/V) revealed no significant difference in frameshift-efficiency. However, 449F lead to a significant increase in frameshift-efficiency (HxB2:6.7% vs. 449F:9.6%) due to a second slippery site and I437V in combination with additional polymorphism (I437V:10.6%). Both effects could be reversed by natural polymorphisms either dissolving the second slippery site or the interaction of the proposed lower hairpin. In PI-resistant HIV only 25 of 81 isolates harbouring 449F or 437V had evidence of a moderate increased frameshift-efficiency.

Conclusions: An increase in frameshift-efficiency is no general mechanism of HIV drug-resistance and the predicted free energy of hairpin do not correlate with measured frameshift-efficiencies. In PI-resistant HIV therapy-associated mutations occur at both C-terminal CS and there are evidence that also selection occur at Pol CS TFP/p6-pol.