Microbiology & Immunology Graduate Student

  Research | Publications | Awards | Posters & Presentations

Melanie Amen Griffiths lab - TX Bio Med Tel: (210) 258-9557 Email: Melanie

Education

B.S., Texas A&M University, College Station

Research

Research interests:

Herpesviruses cause diseases of great medical and veterinary importance for which there are limited treatments and no cures. Macacine herpesvirus 1 (herpes B virus, BV) is an alphaherpesvirus that is endemic in macaque monkeys. Among the nonhuman primate herpesviruses, only BV is known to be pathogenic in humans. A close relative of herpes simplex virus (HSV), BV can zoonotically infect humans to cause a destructive disease with up to 80% mortality if left untreated. With timely antiviral therapy, the mortality rate is ~20% and many of the survivors suffer serious neurological complications and need to maintain antiviral therapy for life. In its natural host, the virus causes recurrent oral and genital lesions similar to that of HSV in humans. In most colonies, between 70 and 90% of macaques are infected. Thus, BV presents a potentially deadly challenge to those handling macaque monkeys or macaque tissues and cells. The Centers for Disease Control and Prevention have classified BV as a Risk Group 4 agent that may only be propagated in a biosafety level 4 (BSL-4) laboratory. Moreover, the virus and viral DNA have been designated by the U.S. Department for Health and Human Services as Select Agents. A better understanding of the neuropathogenesis of BV at the molecular and genetic level will lead to new and specific therapies used to treat those that are most at risk.

MicroRNAs (miRNAs) are key regulators of gene expression. We hypothesized that BV encodes miRNAs that play important roles in the biology of the virus. By deep sequencing RNA harvested from infected cells and naturally infected tissues and validation in transfected cells, I identified 12 novel BV-encoded miRNAs expressed in lytically infected cells, and 4 in latently infected trigeminal ganglia. Further analyses showed that most of the miRNAs exhibited high abundance throughout infection and that some were generated from multiple transcripts with different kinetic classes. Interestingly, miRNAs were detected at early times in the absence of viral gene expression and were present in purified virions. The majority of the miRNAs are encoded by the regions that exhibit the most sequence differences between BV and HSV. Additionally, there is no sequence conservation between BV- and HSV-encoded miRNAs, which may be important for the differences in human diseases caused by BV and HSV.

The remaining part of my project focuses on determining the roles of the miRNAs during lytic and latent infection. I am currently generating recombinant viruses with mutations in the miRNAs and determining the phenotypes during both lytic and latent infection. Additionally, I am generating a neuronal cell culture system to understand the role of the miRNAs in the maintenance and reactivation from latency. Finally, I would like to determine the viral targets of the BV-encoded miRNAs and evaluate their biological significance. I anticipate these data will provide valuable insights into BV pathogenesis, and these insights will be relevant to other herpesviruses.

Publications

• Fan Q., M. Amen, M. Harden, A. Severini, A. Griffiths, R. Longnecker. Herpes B virus Utilizes Human Nectin-1 but Not HVEM or PILRa for Cell-Cell Fusion and Virus Entry. J Virol. 2012 Apr;86(8):4468-76.
• Amen M.A. and A. Griffiths. Packaging of Non-Coding RNAs into Herpesvirus Virions: Comparisons to Coding RNAs. Front Genet. 2011;2:81.
• Amen M.A. and A. Griffiths. Identification and expression analysis of herpes B virus-encoded small RNAs. J Virol. 2011 Jul;85(14):7296-311.
• Venugopalan S.R., X. Li, M.A. Amen, S. Florez, D. Gutierrez, H. Cao, J. Wang, B.A. Amendt. Hierarchical interactions of homeodomain and forkhead transcription factors in regulating odontogenic gene expression. J Biol Chem. 2011 Jun 17;286 (24):21372-83.
• Cao H., S. Flores, M. Amen, T. Huynh, Z. Skobe, A. Baldini, and B.A. Amendt. Tbx1 regulates progenitor cell proliferation in the dental epithelium by modulating Pitx2 activation of p21. Dev Biol. 2010 Nov 15;347(2):289-300.
• Simard A, L. Di Giorgio, M. Amen, A. Westwood, B.A. Amendt, and A.K. Ryan. The Pitx2c N-terminal domain is a critical interaction domain required for asymmetric morphogenesis. Dev Dyn. 2009 Oct;238(10):2459-70.
• Venugopalan, S. R., M.A. Amen, J. Wang, A.C. Cavender, R.N. D'Souza, M. Akerlundt, S.L. Brody, T.A. Hjalt, B.A. Amendt. Novel Expression and Transcriptional Regulation of FoxJ1 During Oro-facial Morphogenesis. Hum Mol Genet. 2008 Dec 1;17(23):3643-54.
• Amen, M., H.M. Espinoza, C. Cox, X. Liang, J. Wang, T.M.E. Link, J.F. Martin, and B.A. Amendt. Chromatin-Associated HMG-17 is a Major Regulator of Homeodomain Transcription Factor Activity Modulated by Wnt/β-catenin Signaling. Nuc Acids Res. 2008 Feb;36(2):462-76.
• Amen, M., X. Liu, U. Vadlamudi, G. Elizondo, E. Diamond, J.F. Engelhardt, and B.A. Amendt. PITX2 and β-catenin Interactions Regulate Lef-1 Isoform Expression. Mol Cell Biol. 2007 Nov;27(21):7560-7573
• Ai, D., J. Wang, M-F, Lu, M. Amen, B.A. Amendt, J.F. Martin. Nuclear Factor-1 and TCF/LEF recognition elements regulate Pitx2 transcription in pituitary development. Mol Cell Biol. 2007 Aug;27(16):5765-5775.
• Diamond, E., M. Amen, Q. Hu, H.M. Espinoza, and B.A. Amendt. Functional Interactions Between DIx2 and Lymphoid Enhancer Factor Regulate Msx2. Nuc Acids Res. 2006;34(20):5951-65.

Awards

2008 - Dean's Excellence Award, UTHSCSA

2010 - Generations Federal Credit Union Future Leaders Scholarship

2011 - Presidential Ambassador Scholar, UTHSCSA

2011 - Travel Grant to 2011 American Society of Virology conference, Univ. of Minnesota

Training Grants

2011-2012 T32 (5T32AI007271-23)

2012-2013 T32 (5T32AI007271-23)

Posters & Presentations

• 34th Annual International Herpesvirus Workshop, oral presentation, "A herpes B virus-encoded microRNA is expressed in infected macaque trigeminal ganglia." Cornell University, July 2009
• 34th Annual International Herpesvirus Workshop, poster presentation, "A herpes B virus-encoded microRNA is expressed in infected macaque trigeminal ganglia." Cornell University, July 2009
• 35th Annual International Herpesvirus Workshop, oral presentation, "Discovery and characterization of Herpes B virus-encoded microRNAs using Deep Sequencing technology." University of Utah, July 2010
• 35th Annual International Herpesvirus Workshop, poster presentation, "Discovery and characterization of Herpes B virus-encoded microRNAs using Deep Sequencing technology." University of Utah, July 2010
• 30th Annual American Society of Virology conference, oral presentation, "Discovery and expression analysis of herpes B virus-encoded microRNAs."University of Minnesota, July 2011
• 31st Annual American Society of Virology conference, poster presentation, "Discovery and functional analysis of herpes B virus-encoded microRNAs."University of Wisconsin, July 2012
• Annual Health Science Center's Health Professions Fair & Science Expo, oral presentation, "Not all Germs are Bad." UTHSCSA, November 2009
• Microbiology Retreat, poster presentation, "Discovery of Herpes B virus-encoded microRNAs." Bandera, TX, November 2009
• UTHSCSA Interview weekend, poster presentation, "Discovery of Herpes B virus-encoded microRNAs." San Antonio, TX, February-March 2010