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VGTI in the News

The Art of Self- Defence (Nature) (click to download)

Janet Douglas, Ph.D.

Viruses and their hosts are in a constant evolutionary arms race to survive. Studying this intricate battle provides us with new insights into understanding anti-viral immunity and new targets for developing anti-viral therapies. My research focuses on the interplay between the host’s defense mechanism to prevent viral release from cells and the various viral countermeasures that have co-evolved. 



A major aspect of my work involves characterizing the mechanism of how the HIV-1 protein Vpu counteracts the host restriction factor BST-2/Tetherin to allow efficient viral egress. We are specifically investigating how Vpu and BST-2 interact and how Vpu uses the host’s own ubiquitin system (for normal protein trafficking and degradation) to circumvent BST-2. In addition, the lab is employing various screening methodologies to identify additional host factors that may be necessary for BST-2 function and/or adaptors important for Vpu’s ability to downmodulate BST-2. 



The viral release restriction imposed by BST-2 is not limited to HIV, but may represent an innate immune mechanism that functions to limit the spread of many, if not all enveloped viruses. The filovirus family is composed of both Marburg and Ebola viruses, which are negative-strand RNA viruses that encode only seven ORFs. Despite their simplicity, human infection results in highly transmissible hemorrhagic fevers with mortality rates approaching 90%. Currently there are no treatments or vaccines for Ebola virus. Like HIV, Ebola virus appears to have evolved a countermeasure to BST-2 in the form of its envelope protein GP. Therefore, we are extending our studies to determine how Ebola virus GP is able to overcome the BST-2 restriction. The GP/BST-2 interaction has the potential to be a new target for the design of effective anti-Ebola strategies. 



Although it is becoming increasingly apparent that BST-2 functions as a broad spectrum, antiviral innate immune mechanism, there are some enveloped viruses, such as the flaviviruses that bud from cells quite differently than HIV and Ebola and therefore may avoid the BST-2 restriction. My lab is also interested in determining whether a member of the flaviviruses, Dengue is also restricted by BST-2 and if so, if it has evolved a counteracting mechanism. 



Biography

After receiving a B.S. in biology at Eckerd College, Janet entered graduate school at the University of Tennessee in Memphis where she received her Ph.D. in 1995 for characterizing the immortalizing and transforming potential of the Adenovirus E1A gene. As a postdoctoral fellow in Dr. Victor Garcia’s laboratory at St. Jude Children’s Hospital in Memphis, TN she developed an HIV-based lentiviral gene delivery system for the transduction of non-dividing human lymphocytes and hematopoietic stem cells. This foray into gene therapy led her into more applied biology, which she pursued at the biotechnology company Systemix in Palo Alto, CA. Here, she extended her work on gene therapy to include a humanized mouse model for assessing the efficacy of lentiviral vectors. Keeping her focus on virology she left the field of gene therapy in 2001 and began working in drug discovery for Gilead Sciences in Foster City, CA. There, she participated in a multi-disciplinary team of scientists attempting to identify novel small molecule inhibitors of respiratory syncytial virus (RSV) fusion and later inhibitors of HIV-1 reverse transcriptase. In 2004 she returned to academic science and began working with Dr. Ashlee Moses at the Vaccine and Gene Therapy Institute (VGTI) at OHSU where they investigated the cellular transformation mechanisms induced by KSHV/HHV-8 infection, as well as determining how the HIV-1 accessory protein Vpu functions to enhance the release of viral particles by counteracting the host immunomodulatory protein BST-2. Currently, as an assistant scientist at the VGTI she is continuing her research on the host’s viral egress restriction and has extended it to other viruses.

Publications
Gustin JK, Douglas JL. BST-2/tetherin: viral tether, viral sensor or both? Future Virol. 2013 Nov;8(11). (doi: 10.2217/fvl.13.96.) [PMID: 24396393, PMCID: PMC3880411]

Douglas JL, Bai Y, Gustin JK, Moses AV. A comparative mutational analysis of HIV-1 Vpu subtypes B and C for the identification of determinants required to counteract BST-2/Tetherin and enhance viral egress. Virology. 2013 Jul 5;441(2):182-96. (doi: 10.1016/j.virol.2013.03.015.) [PMID: 23582304, PMCID: PMC3760674] Epub 2013 Apr 10.

Gustin JK, Douglas JL, Bai Y, Moses AV. Ubiquitination of BST-2 protein by HIV-1 Vpu protein does not require lysine, serine, or threonine residues within the BST-2 cytoplasmic domain. J Biol Chem. 2012 Apr 27;287(18):14837-50. (doi: 10.1074/jbc.M112.349928.) [PMID: 22383521, PMCID: PMC3340234] Epub 2012 Mar 1.

Gustin JK, Moses AV, Früh K, Douglas JL. Viral takeover of the host ubiquitin system. Front Microbiol. 2011 Jul 28;2:161. (doi: 10.3389/fmicb.2011.00161.) [PMID: 21847386, PMCID: PMC3147166] eCollection 2011.

Douglas JL, Gustin JK, Viswanathan K, Mansouri M, Moses AV, Früh K. The great escape: viral strategies to counter BST-2/tetherin. PLoS Pathog. 2010 May 13;6(5):e1000913. (doi: 10.1371/journal.ppat.1000913.) [PMID: 20485522, PMCID: PMC2869331]

Douglas JL, Gustin JK, Moses AV, Dezube BJ, Pantanowitz L. Kaposi Sarcoma Pathogenesis: A Triad of Viral Infection, Oncogenesis and Chronic Inflammation. Transl Biomed. 2010;1(2). [PMID: 23082307, PMCID: PMC3472629] pii: 172.

Mansouri M, Viswanathan K, Douglas JL, Hines J, Gustin J, Moses AV, Früh K. Molecular mechanism of BST2/tetherin downregulation by K5/MIR2 of Kaposi's sarcoma-associated herpesvirus. J Virol. 2009 Oct;83(19):9672-81. (doi: 10.1128/JVI.00597-09.) [PMID: 19605472, PMCID: PMC2748026] Epub 2009 Jul 15.

Douglas JL, Viswanathan K, McCarroll MN, Gustin JK, Früh K, Moses AV. Vpu directs the degradation of the human immunodeficiency virus restriction factor BST-2/Tetherin via a {beta}TrCP-dependent mechanism. J Virol. 2009 Aug;83(16):7931-47. (doi: 10.1128/JVI.00242-09.) [PMID: 19515779, PMCID: PMC2715753] Epub 2009 Jun 10.

Douglas JL, Whitford JG, Moses AV. Characterization of c-Kit expression and activation in KSHV-infected endothelial cells. Virology. 2009 Aug 1;390(2):174-85. (doi: 10.1016/j.virol.2009.05.011.) [PMID: 19501868, PMCID: PMC3489927] Epub 2009 Jun 6.