Site-selective probing of cTAR destabilization highlights the necessary plasticity of the HIV-1 nucleocapsid protein to chaperone the first strand transfer

Nucleic Acids Research

Volumn 41, Issue 9, 2013, Pages 5036-5048

  Godet, Julien ^a,b   Kenfack, Cyril ^a,c   Przybilla, Frédéric ^a   Richert, Ludovic ^a   Duportail, Guy ^a   Mély, Yves ^a  

^a UNIVERSITÉ DE STRASBOURG   (France)

^b UNIVERSITY HOSPITAL OF STRASBOURG   (France)

^c UNIVERSITY OF DOUALA   (Cameroon)

Author keywords

[No Author keywords available]

Indexed keywords

NUCLEOCAPSID PROTEIN; PROTEIN NCP7; UNCLASSIFIED DRUG; VIRUS DNA;

ARTICLE; DNA RESPONSIVE ELEMENT; DNA SEQUENCE; DNA STRAND; HUMAN IMMUNODEFICIENCY VIRUS 1; NONHUMAN; PRIORITY JOURNAL; PROTEIN DOMAIN; SEQUENCE ALIGNMENT; TRANSACTIVATION RESPONSIVE ELEMENT; VIRUS NUCLEOCAPSID;

2-AMINOPURINE; BASE SEQUENCE; CONSERVED SEQUENCE; DNA, VIRAL; GAG GENE PRODUCTS, HUMAN IMMUNODEFICIENCY VIRUS; HIV LONG TERMINAL REPEAT; MUTATION; NUCLEIC ACID CONFORMATION; NUCLEIC ACID DENATURATION; SPECTROMETRY, FLUORESCENCE;

EID: 84877309549     PISSN: 03051048     EISSN: 13624962     Source Type: Journal    
DOI: 10.1093/nar/gkt164     Document Type: Article

References (89)

1. Morellet, N., Jullian, N., De Rocquigny, H., Maigret, B., Darlix, J.L. and Roques, B.P. (1992) Determination of the structure of the nucleocapsid protein NCp7 from the human immunodeficiency virus type 1 by 1H NMR. EMBO J., 11, 3059-3065.
2. Summers, M.F., Henderson, L.E., Chance, M.R., Bess, J.W., South, T.L., Blake, P.R., Sagi, I., Perez-Alvarado, G., Sowder, R.C. and Hare, D.R. (1992) Nucleocapsid zinc fingers detected in retroviruses: EXAFS studies of intact viruses and the solution-state structure of the nucleocapsid protein from HIV-1. Protein Sci., 1, 563-574.
3. Darlix, J.L., Cristofari, G., Rau, M., Pechoux, C., Berthoux, L. and Roques, B. (2000) Nucleocapsid protein of human immunodeficiency virus as a model protein with chaperoning functions and as a target for antiviral drugs. Adv. Pharmacol., 48, 345-372.
4. Darlix, J.-L., Garrido, J.L., Morellet, N., Mely, Y. and De Rocquigny, H. (2007) Properties, functions, and drug targeting of the multifunctional nucleocapsid protein of the human immunodeficiency virus. Adv. Pharmacol., 55, 299-346.
5. Levin, J.G., Guo, J., Rouzina, I. and Musier-Forsyth, K. (2005) Nucleic acid chaperone activity of HIV-1 nucleocapsid protein: critical role in reverse transcription and molecular mechanism. Prog. Nucleic Acid Res. Mol. Biol., 80, 217-286.
6. Thomas, J.A. and Gorelick, R.J. (2008) Nucleocapsid protein function in early infection processes. Virus Res., 134, 39-63.
7. Mirambeau, G., Lyonnais, S. and Gorelick, R.J. (2010) Features, processing states, and heterologous protein interactions in the modulation of the retroviral nucleocapsid protein function. RNA Biol., 7, 85-95.
8. Muriaux, D. and Darlix, J.-L. (2010) Properties and functions of the nucleocapsid protein in virus assembly. RNA Biol., 7, 744-753.
9. Kafaie, J., Song, R., Abrahamyan, L., Mouland, A.J. and Laughrea, M. (2008) Mapping of nucleocapsid residues important for HIV-1 genomic RNA dimerization and packaging. Virology, 375, 592-610.
10. Lee, S.-K., Harris, J. and Swanstrom, R. (2009) A strongly transdominant mutation in the human immunodeficiency virus type 1 gag gene defines an Achilles heel in the virus life cycle. J. Virol., 83, 8536-8543.
11. Ohishi, M., Nakano, T., Sakuragi, S., Shioda, T., Sano, K. and Sakuragi, J. (2011) The relationship between HIV-1 genome RNA dimerization, virion maturation and infectivity. Nucleic Acids Res., 39, 3404-3417.
12. Herschlag, D. (1995) RNA chaperones and the RNA folding problem. J. Biol. Chem., 270, 20871-20874.
13. Rein, A., Henderson, L.E. and Levin, J.G. (1998) Nucleic-acid-chaperone activity of retroviral nucleocapsid proteins: significance for viral replication. Trends Biochem. Sci., 23, 297-301.
14. Cristofari, G. and Darlix, J.-L. (2002) The ubiquitous nature of RNA chaperone proteins. Prog. Nucleic Acid Res. Mol. Biol., 72, 223-268.
15. Woodson, S.A. (2010) Taming free energy landscapes with RNA chaperones. RNA Biol., 7, 677-686.
16. Levin, J.G., Mitra, M., Mascarenhas, A. and Musier-Forsyth, K. (2010) Role of HIV-1 nucleocapsid protein in HIV-1 reverse transcription. RNA Biol., 7, 754-774.
17. Darlix, J.-L., Godet, J., Ivanyi-Nagy, R., Fosse, P., Mauffret, O. and Mely, Y. (2011) Flexible nature and specific functions of the HIV-1 nucleocapsid protein. J. Mol. Biol., 410, 565-581.
18. You, J.C. and McHenry, C.S. (1994) Human immunodeficiency virus nucleocapsid protein accelerates strand transfer of the terminally redundant sequences involved in reverse transcription. J. Biol. Chem., 269, 31491-31495.
19. Guo, J., Henderson, L.E., Bess, J., Kane, B. and Levin, J.G. (1997) Human immunodeficiency virus type 1 nucleocapsid protein promotes efficient strand transfer and specific viral DNA synthesis by inhibiting TAR-dependent self-priming from minus-strand strong-stop DNA. J. Virol., 71, 5178-5188.
20. Godet, J., De Rocquigny, H., Raja, C., Glasser, N., Ficheux, D., Darlix, J.-L. and Mely, Y. (2006) During the early phase of HIV-1 DNA synthesis, nucleocapsid protein directs hybridization of the TAR complementary sequences via the ends of their double-stranded stem. J. Mol. Biol., 356, 1180-1192.
21. Vo, M.-N., Barany, G., Rouzina, I. and Musier-Forsyth, K. (2009) HIV-1 nucleocapsid protein switches the pathway of transactivation response element RNA/DNA annealing from loop-loop 'kissing' to 'zipper'. J. Mol. Biol., 386, 789-801.
22. Darlix, J.L., Vincent, A., Gabus, C., De Rocquigny, H. and Roques, B. (1993) Trans-activation of the 5' to 3' viral DNA strand transfer by nucleocapsid protein during reverse transcription of HIV1 RNA. C. R. Acad. Sci. III., 316, 763-771.
23. Lapadat-Tapolsky, M., Pernelle, C., Borie, C. and Darlix, J.L. (1995) Analysis of the nucleic acid annealing activities of nucleocapsid protein from HIV-1. Nucleic Acids Res., 23, 2434-2441.
24. Stoylov, S.P., Vuilleumier, C., Stoylova, E., De Rocquigny, H., Roques, B.P., Gerard, D. and Mely, Y. (1997) Ordered aggregation of ribonucleic acids by the human immunodeficiency virus type 1 nucleocapsid protein. Biopolymers, 41, 301-312.
25. Williams, M.C., Rouzina, I., Wenner, J.R., Gorelick, R.J., Musier-Forsyth, K. and Bloomfield, V.A. (2001) Mechanism for nucleic acid chaperone activity of HIV-1 nucleocapsid protein revealed by single molecule stretching. Proc. Natl Acad. Sci. USA, 98, 6121-6126.
26. Boudier, C., Storchak, R., Sharma, K.K., Didier, P., Follenius-Wund, A., Muller, S., Darlix, J.-L. and Mely, Y. (2010) The mechanism of HIV-1 Tat-directed nucleic acid annealing supports its role in reverse transcription. J. Mol. Biol., 400, 487-501.
27. Sharma, K., kant, Didier, P., Darlix, J.L., De Rocquigny, H., Bensikaddour, H., Lavergne, J.-P., Penin, F., Lessinger, J.-M. and Mely, Y. (2010) Kinetic analysis of the nucleic acid chaperone activity of the hepatitis C virus core protein. Nucleic Acids Res., 38, 3632-3642.
28. Guichard, C., Ivanyi-Nagy, R., Sharma, K.K., Gabus, C., Marc, D., Mely, Y. and Darlix, J.-L. (2011) Analysis of nucleic acid chaperoning by the prion protein and its inhibition by oligonucleotides. Nucleic Acids Res., 39, 8544-8558.
29. Bernacchi, S., Stoylov, S., Piemont, E., Ficheux, D., Roques, B.P., Darlix, J.L. and Mely, Y. (2002) HIV-1 nucleocapsid protein activates transient melting of least stable parts of the secondary structure of TAR and its complementary sequence. J. Mol. Biol., 317, 385-399.
30. Azoulay, J., Clamme, J.P., Darlix, J.L., Roques, B.P. and Mely, Y. (2003) Destabilization of the HIV-1 complementary sequence of TAR by the nucleocapsid protein through activation of conformational fluctuations. J. Mol. Biol., 326, 691-700.
31. Beltz, H., Azoulay, J., Bernacchi, S., Clamme, J.-P., Ficheux, D., Roques, B., Darlix, J.-L. and Mely, Y. (2003) Impact of the terminal bulges of HIV-1 cTAR DNA on its stability and the destabilizing activity of the nucleocapsid protein NCp7. J. Mol. Biol., 328, 95-108.
32. Cosa, G., Harbron, E.J., Zeng, Y., Liu, H.-W., O'Connor, D.B., Eta-Hosokawa, C, Musier-Forsyth, K. and Barbara, P.F. (2004) Secondary structure and secondary structure dynamics of DNA hairpins complexed with HIV-1 NC protein. Biophys. J., 87, 2759-2767.
33. Liu, H.-W., Cosa, G., Landes, C.F., Zeng, Y., Kovaleski, B.J., Mullen, D.G., Barany, G., Musier-Forsyth, K. and Barbara, P.F. (2005) Single-molecule FRET studies of important intermediates in the nucleocapsid-protein-chaperoned minus-strand transfer step in HIV-1 reverse transcription. Biophys. J., 89, 3470-3479.
34. Cosa, G, Zeng, Y., Liu, H.-W., Landes, C.F., Makarov, D.E., Musier-Forsyth, K. and Barbara, P.F. (2006) Evidence for non-two-state kinetics in the nucleocapsid protein chaperoned opening of DNA hairpins. J. Phys. Chem. B, 110, 2419-2426.
35. Beltz, H, Clauss, C, Piemont, E., Ficheux, D., Gorelick, R.J., Roques, B., Gabus, C, Darlix, J.-L., De Rocquigny, H. and Mely, Y. (2005) Structural determinants of HIV-1 nucleocapsid protein for cTAR DNA binding and destabilization, and correlation with inhibition of self-primed DNA synthesis. J. Mol. Biol., 348, 1113-1126.
36. De Guzman, R.N, Wu, Z.R., Stalling, C.C, Pappalardo, L., Borer, P.N. and Summers, M.F. (1998) Structure of the HIV-1 nucleocapsid protein bound to the SL3 psi-RNA recognition element. Science, 279, 384-388.
37. Fisher, R.J., Rein, A., Fivash, M., Urbaneja, MA., Casas-Finet, J.R., Medaglia, M. and Henderson, L.E. (1998) Sequence-specific binding of human immunodeficiency virus type 1 nucleocapsid protein to short oligonucleotides. J. Virol., 72, 1902-1909.
38. Morellet, N, Demene, H, Teilleux, V., Huynh-Dinh, T., De Rocquigny, H, Fournie-Zaluski, M.C. and Roques, B.P. (1998) Structure of the complex between the HIV-1 nucleocapsid protein NCp7 and the single-stranded pentanucleotide d(ACGCC). J. Mol. Biol., 283, 419-434.
39. Vuilleumier, C, Bombarda, E., Morellet, N, Gerard, D., Roques, B.P. and Mely, Y. (1999) Nucleic acid sequence discrimination by the HIV-1 nucleocapsid protein NCp7: a fluorescence study. Biochemistry, 38, 16816-16825.
40. Amarasinghe, GK., Zhou, J., Miskimon, M., Chancellor, K.J., McDonald, J.A., Matthews, A.G, Miller, R.R., Rouse, M.D. and Summers, M.F. (2001) Stem-loop SL4 of the HIV-1 psi RNA packaging signal exhibits weak affinity for the nucleocapsid protein. structural studies and implications for genome recognition. J. Mol. Biol., 314, 961-970.
41. Bourbigot, S., Ramalanjaona, N, Boudier, C, Salgado, GF.J., Roques, B.P., Mely, Y., Bouaziz, S. and Morellet, N. (2008) How the HIV-1 nucleocapsid protein binds and destabilises the (-)primer binding site during reverse transcription. J. Mol. Biol., 383, 1112-1128.
42. Mori, M., Dietrich, U., Manetti, F. and Botta, M. (2010) Molecular dynamics and DFT study on HIV-1 nucleocapsid protein-7 in complex with viral genome. J. Chem. Inf. Model., 50, 638-650.
43. Bazzi, A., Zargarian, L., Chaminade, F., Boudier, C, De Rocquigny, H, Rene, B., Mely, Y., Fosse, P. and Mauffret, O. (2011) Structural insights into the cTAR DNA recognition by the HIV-1 nucleocapsid protein: role of sugar deoxyriboses in the binding polarity of NC. Nucleic Acids Res., 39, 3903-3916.
44. Avilov, S.V., Piemont, E., Shvadchak, V., De Rocquigny, H. and Mely, Y. (2008) Probing dynamics of HIV-1 nucleocapsid protein/target hexanucleotide complexes by 2-aminopurine. Nucleic Acids Res., 36, 885-896.
45. Avilov, S.V., Godet, J., Piemont, E. and Mely, Y. (2009) Site-specific characterization of HIV-1 nucleocapsid protein binding to oligonucleotides with two binding sites. Biochemistry, 48, 2422-2430.
46. Godet, J., Ramalanjaona, N., Sharma, K.K., Richert, L., De Rocquigny, H., Darlix, J.-L., Duportail, G. and Mely, Y. (2011) Specific implications of the HIV-1 nucleocapsid zinc fingers in the annealing of the primer binding site complementary sequences during the obligatory plus strand transfer. Nucleic Acids Res., 39, 6633-6645.
47. De Rocquigny, H., Ficheux, D., Gabus, C., Fournie-Zaluski, M.C., Darlix, J.L. and Roques, B.P. (1991) First large scale chemical synthesis of the 72 amino acid HIV-1 nucleocapsid protein NCp7 in an active form. Biochem. Biophys. Res. Commun., 180, 1010-1018.
48. Livesey, A.K. and Brochon, J.C. (1987) Analyzing the distribution of decay constants in pulse-fluorimetry using the maximum entropy method. Biophys. J., 52, 693-706.
49. Brochon, J.C. (1994) Maximum entropy method of data analysis in time-resolved spectroscopy. Methods Enzymol., 240, 262-311.
50. Development Core Team, R. (2009) R: A Language and Environment for Statistical Computing. R Development Core Team, Vienna, Austria.
51. Schneider, T.D. and Stephens, R.M. (1990) Sequence logos: a new way to display consensus sequences. Nucleic Acids Res., 18, 6097-6100.
52. Ward, D.C., Reich, E. and Stryer, L. (1969) Fluorescence studies of nucleotides and polynucleotides. I. Formycin, 2-aminopurine riboside, 2, 6-diaminopurine riboside, and their derivatives. J. Biol. Chem., 244, 1228-1237.
53. Jean, J.M. and Hall, K.B. (2001) 2-Aminopurine fluorescence quenching and lifetimes: role of base stacking. Proc. Natl Acad. Sci. USA, 98, 37-41.
54. Jean, J.M. and Hall, K.B. (2002) 2-Aminopurine electronic structure and fluorescence properties in DNA. Biochemistry, 41, 13152-13161.
55. Wan, C., Xia, T., Becker, H.-C. and Zewail, A.H. (2005) Ultrafast unequilibrated charge transfer: A new channel in the quenching of fluorescent biological probes. Chem. Phys. Lett., 412, 158-163.
56. Jean, J.M. and Hall, K.B. (2004) Stacking-unstacking dynamics of oligodeoxynucleotide trimers. Biochemistry, 43, 10277-10284.
57. Guest, C.R., Hochstrasser, R.A., Sowers, L.C. and Millar, D.P. (1991) Dynamics of mismatched base pairs in DNA. Biochemistry, 30, 3271-3279.
58. Zargarian, L., Kanevsky, I., Bazzi, A., Boynard, J., Chaminade, F., Fosse, P. and Mauffret, O. (2009) Structural and dynamic characterization of the upper part of the HIV-1 cTAR DNA hairpin. Nucleic Acids Res., 37, 4043-4054.
59. Xu, D., Evans, K.O. and Nordlund, T.M. (1994) Melting and premelting transitions of an oligomer measured by DNA base fluorescence and absorption. Biochemistry, 33, 9592-9599.
60. Jiao, Y., Stringfellow, S. and Yu, H. (2002) Distinguishing 'looped-out' and 'stacked-in' DNA bulge conformation using fluorescent 2-aminopurine replacing a purine base. J. Biomol. Struct. Dyn., 19, 929-934.
61. Jung, J. and Van Orden, A. (2006) A three-state mechanism for DNA hairpin folding characterized by multiparameter fluorescence fluctuation spectroscopy. J. Am. Chem. Soc., 128, 1240-1249.
62. Lin, M.M., Meinhold, L., Shorokhov, D. and Zewail, A.H. (2008) Unfolding and melting of DNA (RNA) hairpins: the concept of structure-specific 2D dynamic landscapes. Phys. Chem. Chem. Phys., 10, 4227-4239.
63. Neely, R.K., Daujotyte, D., Grazulis, S., Magennis, S.W., Dryden, D.T.F., Klimasauskas, S. and Jones, A.C. (2005) Time-resolved fluorescence of 2-aminopurine as a probe of base flipping in M.HhaI-DNA complexes. Nucleic Acids Res., 33, 6953-6960.
64. Neely, R.K., Tamulaitis, G., Chen, K., Kubala, M., Siksnys, V. and Jones, A.C. (2009) Time-resolved fluorescence studies of nucleotide flipping by restriction enzymes. Nucleic Acids Res., 37, 6859-6870.
65. Larsen, O.F., Van Stokkum, I.H., Gobets, B., Van Grondelle, R. and Van Amerongen, H. (2001) Probing the structure and dynamics of a DNA hairpin by ultrafast quenching and fluorescence depolarization. Biophys. J., 81, 1115-1126.
66. Lakowicz, J.R. (2006) Principles of Fluorescence Spectroscopy. Springer, New York, USA.
67. Kanevsky, I., Chaminade, F., Chen, Y., Godet, J., Rene, B., Darlix, J.-L., Mely, Y., Mauffret, O. and Fosse, P. (2011) Structural determinants of TAR RNA-DNA annealing in the absence and presence of HIV-1 nucleocapsid protein. Nucleic Acids Res., 39, 8148-8162.
68. Guo, J., Wu, T., Anderson, J., Kane, B.F., Johnson, D.G., Gorelick, R.J., Henderson, L.E. and Levin, J.G. (2000) Zinc finger structures in the human immunodeficiency virus type 1 nucleocapsid protein facilitate efficient minus-and plus-strand transfer. J. Virol., 74, 8980-8988.
69. Helene, C. and Maurizot, J.C. (1981) Interactions of oligopeptides with nucleic acids. CRC Crit. Rev. Biochem., 10, 213-258.
70. Dill, K.A. and Bromberg, S. (2002) Molecular Driving Forces: Statistical Thermodynamics in Chemistry and Biology, 1st edn. Garland Science, London, UK.
71. Stewart-Maynard, K.M., Cruceanu, M., Wang, F., Vo, M.-N., Gorelick, R.J., Williams, M.C., Rouzina, I. and Musier-Forsyth, K. (2008) Retroviral nucleocapsid proteins display nonequivalent levels of nucleic acid chaperone activity. J. Virol., 82, 10129-10142.
72. Vo, M.-N., Barany, G., Rouzina, I. and Musier-Forsyth, K. (2006) Mechanistic studies of mini-TAR RNA/DNA annealing in the absence and presence of HIV-1 nucleocapsid protein. J. Mol. Biol., 363, 244-261.
73. Schneider, T.D., Stormo, G.D., Gold, L. and Ehrenfeucht, A. (1986) Information content of binding sites on nucleotide sequences. J. Mol. Biol., 188, 415-431.
74. Schneider, T.D. (2002) Consensus sequence Zen. Appl. Bioinformatics, 1, 111-119.
75. Berkhout, B., Klaver, B. and Das, A.T. (1997) Forced evolution of a regulatory RNA helix in the HIV-1 genome. Nucleic Acids Res., 25, 940-947.
76. Zuker, M. (2003) Mfold web server for nucleic acid folding and hybridization prediction. Nucleic Acids Res., 31, 3406-3415.
77. Godet, J. and Mely, Y. (2010) Biophysical studies of the nucleic acid chaperone properties of the HIV-1 nucleocapsid protein. RNA Biol., 7, 687-699.
78. Cruceanu, M., Gorelick, R.J., Musier-Forsyth, K., Rouzina, I. and Williams, M.C. (2006) Rapid kinetics of protein-nucleic acid interaction is a major component of HIV-1 nucleocapsid protein's nucleic acid chaperone function. J. Mol. Biol., 363, 867-877.
79. Doetsch, M., Schroeder, R. and Furtig, B. (2011) Transient RNA-protein interactions in RNA folding. FEBS J., 278, 1634-1642.
80. Nag, N., Rao, B.J. and Krishnamoorthy, G. (2007) Altered dynamics of DNA bases adjacent to a mismatch: a cue for mismatch recognition by MutS. J. Mol. Biol., 374, 39-53.
81. Bazzi, A., Zargarian, L., Chaminade, F., De Rocquigny, H., Rene, B., Mely, Y., Fosse, P. and Mauffret, O. (2012) Intrinsic nucleic acid dynamics modulates HIV-1 nucleocapsid protein binding to its targets. PLoS One, 7, e38905.
82. Gherghe, C., Lombo, T., Leonard, C.W., Datta, S.A.K., Bess, J.W. Jr, Gorelick, R.J., Rein, A. and Weeks, K.M. (2010) Definition of a high-affinity Gag recognition structure mediating packaging of a retroviral RNA genome. Proc. Natl Acad. Sci. USA, 107, 19248-19253.
83. Klaver, B. and Berkhout, B. (1994) Evolution of a disrupted TAR RNA hairpin structure in the HIV-1 virus. EMBO J., 13, 2650-2659.
84. Cruceanu, M., Urbaneja, M.A., Hixson, C.V., Johnson, D.G., Datta, S.A., Fivash, M.J., Stephen, A.G., Fisher, R.J., Gorelick, R.J., Casas-Finet, J.R. et al. (2006) Nucleic acid binding and chaperone properties of HIV-1 Gag and nucleocapsid proteins. Nucleic Acids Res., 34, 593-605.
85. Henriet, S., Sinck, L., Bec, G., Gorelick, R.J., Marquet, R. and Paillart, J.-C. (2007) Vif is a RNA chaperone that could temporally regulate RNA dimerization and the early steps of HIV-1 reverse transcription. Nucleic Acids Res., 35, 5141-5153.
86. Derrington, E., Gabus, C., Leblanc, P., Chnaidermann, J., Grave, L., Dormont, D., Swietnicki, W., Morillas, M., Marck, D., Nandi, P. et al. (2002) PrPC has nucleic acid chaperoning properties similar to the nucleocapsid protein of HIV-1. C. R. Biol., 325, 17-23.
87. De Rocquigny, H., Shvadchak, V., Avilov, S., Dong, C.Z., Dietrich, U., Darlix, J.-L. and Mely, Y. (2008) Targeting the viral nucleocapsid protein in anti-HIV-1 therapy. Mini Rev. Med. Chem., 8, 24-35.
88. Goldschmidt, V., Miller Jenkins, L.M., De Rocquigny, H., Darlix, J.-L. and Mely, Y. (2010) The nucleocapsid protein of HIV-1 as a promising therapeutic target for antiviral drugs. HIV Ther., 4, 179-198.
89. Grigorov, B., Bocquin, A., Gabus, C., Avilov, S., Mely, Y., Agopian, A., Divita, G., Gottikh, M., Witvrouw, M. and Darlix, J.-L. (2011) Identification of a methylated oligoribonucleotide as a potent inhibitor of HIV-1 reverse transcription complex. Nucleic Acids Res., 39, 5586-5596.