Overview of the Tolbert Group

Research in the Tolbert group endeavors to understand the molecular mechanisms RNA viruses use to express their genomes. Nuclear magnetic resonance (NMR) spectroscopy and other solution biophysical methods are used to determine 3D structures and physiochemical properties of viral RNA regulatory elements both free and bound to their cognate host proteins. The research in the group is highly interdisciplinary where trainees have the opportunity to gain experience in biophysical chemistry, molecular biology, computational biology, and virology. Our primary focus is to better understand how the human immunodeficiency virus (HIV), the etiological agent of AIDS, regulates RNA processing events. Towards that end, we determined the first high-resolution structure of a key HIV regulatory RNA, the Exon Splicing Silencer 3 (ESS3), and elucidated its thermodynamic binding profile to the human protein hnRNP A1. Other projects include determining the molecular mechanisms of transcriptional control of HIV latency and translational control of Enterovirus 71 (EV71) — the etiological agent of Hand, Foot, and Mouth Disease — and studying the role of RNA-binding proteins in infection by SARS-CoV-2 (the virus responsible for COVID-19).

For a list of publications on PubMed, click here.

Research Techniques

NMR spectroscopy, isothermal titration calorimetry, differential scanning calorimetry, protein chromatography, X-ray crystallography, and molecular dynamics simulations

Group Affiliations

    The Center for HIV-1 RNA Studies (CRNA) »
    The Center for AIDS Research (CFAR) »

Selected Publications

Chiu L.-Y., Emery A., Sugarman A., Kendrick N., Luo L., Ford W., Swanstrom R., Tolbert B.S. (2022). “Encoded Conformational Dynamics of the HIV Splice Site A3 Regulatory Locus: Implications for Differential Binding of hnRNP Splicing Auxiliary Factors.” J. Molec. Biol. 167728. ISSN: 0022-2836. DOI: 10.1016/j.jmb.2022.167728.

Zafferani M., Haddad C., Luo L., Davila-Calderon J., Chiu L.-Y., Mugisha C.S., Monaghan A.G., Kennedy A.A., Yesselman J.D., Gifford R.J., Tai A.W., Kutluay S.B., Li M.-L., Brewer G., Tolbert B.S., and Hargrove A.E. (2021). “Amilorides inhibit SARS-CoV-2 replication in vitro by targeting RNA structures.” Sci. Adv. 7(48), eabl6096. DOI: 10.1126/sciadv.abl6096.

Davila-Calderon J., Patwardhan N.N., Chiu L.-Y., Sugarman A., Cai Z., Penumutchu S.R., Li M.-L., Brewer G., Hargrove A.E., and Tolbert B.S. (2020). “IRES-targeting small molecule inhibits enterovirus 71 replication via allosteric stabilization of a ternary complex.” Nat. Commun. 11(4775). DOI: 10.1038/s41467-020-18594-3.

Li M.-L., Lin J.-Y., Chen B.-S., Weng K.-F., Shih S.-R., Dávila-Calderón J., Tolbert B.S., and Brewer G. (2019). “EV71 3C protease induces apoptosis by cleavage of hnRNP A1 to promote apaf-1 translation.” PLoS ONE 14(9), e0221048. DOI: 10.1371/journal.pone.0221048.

Penumutchu S.R., Chiu L.-Y., Meagher J.L., Hansen A.L., Stuckey J.A., and Tolbert B.S. (2018). “Differential Conformational Dynamics Encoded by the Linker between Quasi RNA Recognition Motifs of Heterogeneous Nuclear Ribonucleoprotein H.” J. Am. Chem. Soc. 140(37), 11661-11673. DOI: 10.1021/jacs.8b05366.

Tolbert M., Morgan C.E., Pollum M, Crespo C., Li M.-L., Brewer G., and Tolbert B.S. (2017). “HnRNP A1 Alters the Conformational Dynamics of a Conserved EV IRES Domain to Stimulate Viral Translation.” J. Mol. Biol. 429(19), 2841-2458. DOI: 10.1016/j.jmb.2017.06.007.

Jain N., Lin H.C., Morgan C.E., Harris M.E., and Tolbert B.S. (2017). “Rules of RNA Specificity of hnRNP A1 Revealed by Global and Quantitative Analysis of its Affinity Distribution.” Proc. Natl. Acad. Sci. 114(9), 2206-2211. DOI: 10.1073/pnas.1616371114.

Jain, N., Morgan C.E., Rife B.D., Salemi M., and Tolbert B.S. (2016). “Solution Structure of the HIV-1 Intronic Splicing Silencer and its Interactions with the UP1 Domain of hnRNP A1.” J. Biol. Chem. 291(5), 2331-2344. DOI: 10.1074/jbc.M115.674564.

Morgan C.E., Meagher J.L., Levengood J.D., Delproposto J., Rollins C., Stuckey J.A., and Tolbert B.S. (2015). “The First Crystal Structure of the UP1 Domain of hnRNP A1 Bound to RNA Reveals a New Look for an Old RNA Binding Protein.” J. Mol. Biol. 427(20), 3241-3257. DOI: 10.1016/j.jmb.2015.05.009.

Rollins C., Levengood J.D., Rife B.D., Salemi M., and Tolbert B.S. (2014). “Thermodynamic and Phylogenetic Insights into hnRNP A1 Recognition of the HIV-1 Exon Splicing Silencer 3 Element.” Biochemistry 53(13), 2172-2184. DOI: 10.1021/bi500180p.

Levengood J.D., Tolbert M., Li M.-L., and Tolbert, B.S. (2013). “High-Affinity interactions of hnRNP A1 with conserved RNA structural elements is required for translation and replication of Enterovirus 71.” RNA Biology 10(7), 1136-1145. DOI: 10.4161/rna.25107.

Blakeley B.D., DePorter S.M., Mohan U., Burai R., Tolbert B.S., and McNaughton B.R. (2012). “Methods for identifying and characterizing interactions involving RNA.” Tetrahedron 68(43), 8837-8855. DOI: 10.1016/j.tet.2012.07.001.

Levengood J.D., Rollins C., Mishler C.H., Johnson C.A., Miner G., Rajan P., Znosko B.M., and Tolbert B.S. (2012). “Solution structure of the HIV-1 exon splicing silencer 3”. J. Mol. Biol. 415(4), 680-698. DOI: 10.1016/j.jmb.2011.11.034.

Feldmann E.A., Ni S., Sahu I.D., Mishler C.H., Risser D.D., Murakami J.L., Tom S.K., McCarrick R.M., Lorigan G.A., Tolbert B.S., Callahan S.M., and Kennedy M.A. (2011). “Evidence for direct binding between HetR from Anabaena sp. PCC 7129 and PatS-5”. Biochemistry 50(43), 9212-9224. DOI: 10.1021/bi201226e.

Miyazaki Y., Irobalieva R.N., Tolbert B.S., Smalls-Mantey A., Iyalla K., Loeliger K., D’Souza V., Khant H., Schmid M.F., Garcia E.L., Telesnitsky A., Chiu W., and Summers M.F. (2010). “Structure of a conserved retroviral RNA packaging element by NMR spectroscopy and cryo-electron tomography”. J. Mol. Biol. 404(5), 751-772. DOI: 10.1016/j.jmb.2010.09.009.

Tolbert B.S., Miyazaki Y., Barton S., Kinde B., Stark P., Singh R., Bax A., Case D., Summers M.F. (2010). “Major groove width variations in RNA structures determined by NMR and impact of 13C residual chemical shift anisotropy and 1H-13C residual dipolar coupling on refinement”. J. Biomol. NMR 47(3), 205-219. DOI: 10.1007/s10858-010-9424-x.

Book Chapters

Tolbert, B.S.; Rollins, C.; Levengood, J.D.; Luo, L.; and Rajan, P. (2013). “Probing the structural basis of retroviral RNA functions via NMR spectroscopy”. RNA Nanotechnology; ch. 8.