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Lynda A. Morrison, Ph.D.


Lynda A. Morrison, Ph.D.
Molecular Microbiology & Immunology
Saint Louis University School of Medicine

Ph.D., Washington University, 1988

Doisy Research Center
1100 South Grand Blvd
Office/Lab 607/657
Saint Louis, MO 63104
Office: 977-8874
Lab: 977-8873

Lynda A. Morrison, Ph.D.

Research Summary:

Herpes simplex virus 1 (HSV-1) is a ubiquitous virus that causes potentially blinding eye disease as well as common cold sores. HSV-2 is sexually transmitted and affects nearly one fourth of the U.S. population. HSV-2 causes recurrent genital sores and severely affects children acquiring infection from their mothers during birth. Infection with HSV-2 also increases the risk of HIV infection. The primary goals of our research are to develop a vaccine strain that protects against HSV, and to elucidate mechanisms by which HSV interferes with immune responses to promote its infection.

To develop a vaccine, we utilize virus strains containing an engineered mutation in a gene essential for virus replication. These viruses express numerous proteins in infected cells but do not reproduce and spread, making them relatively immunogenic and safe. We are using molecular genetic techniques and our knowledge of viral genetics underlying pathogenesis to improve immune responses to the replication-defective prototype vaccine. Thus, we are mutating genes that encode viral proteins involved in immune evasion, and inserting host molecules that stimulate immune responses into the virus genome. Mice immunized with replication-defective mutants of HSV-1 or HSV-2 develop a long-lived immune response that protects them against disease upon ocular or genital infection, respectively. We are determining the role of different immune effectors in mediating protection against sexually transmitted disease, and the importance of molecules that stimulate antiviral T cells.

A collection of viral proteins packed into the tegument layer of the virus particle perform essential functions that regulate viral and host cell processes. We are studying several of these proteins to understand in greater depth their roles in HSV-2 infection. The virion host shutoff (vhs) tegument protein rapidly degrades host mRNA to assert control over host protein synthesis. We found that HSV-2 vhs contributes to virulence primarily by blockade of the host type I IFN response, and we are investigating the mechanism of inhibition. The ICP34.5 tegument protein of HSV-1 counteracts several cellular antiviral responses. Interestingly, the HSV-2 homolog is structurally dissimilar and we are investigating whether its functional capacities are also different. The UL13 kinase found in the tegument phosphorylates other viral tegument components and cellular proteins to alter their functional activity. Targets of HSV-2 UL13 and the consequences of UL13-mediated phosphorylation are ongoing areas of investigation.

UL13 and lamins colocalization

Distribution of HSV-2 UL13 mutant K176A (green) and nulcear lamins A/C (red)

Lab Members:

L to R: Sri Chiravuri, Lynda Morrison, Greg Delassus, Hong Wang, Maria Korom, and Katie Davis


Korom M, Wylie KM, Wang H, Davis KL, Sangabathula MS, DeLassus GS, and LA Morrison. 2013. A pro-autophagic antiviral role for the cellular prion protein identified by infection with a herpes simplex virus 1 ICP34.5 mutant. Journal of Virology, 87:5882-94.

Wang H, Davido DJ, and Morrison LA. 2013. HSV-1 strain McKrae is more neuroinvasive than HSV-1 KOS after corneal or vaginal inoculation in mice.  Virus Res., 173:436-440.

Macdonald SJ, Mostafa HH, Morrison LA, and Davido DJ. 2012. Genome sequence of herpes simplex virus 1 strain KOS. Journal of Virology, 86:6371-6372.

Macdonald SJ, Mostafa HH, Morrison LA, and Davido DJ. 2012. Genome sequence of herpes simplex virus 1 strain McKrae. Journal of Virology, 86:9540-9541.

Mbong EF, Woodley L, Dunkerley E, SchrimpfJS, Morrison LA and Duffy C. 2012. Deletion of the HSV-1 UL49 gene results in mRNA and protein translation defects that are complemented by secondary mutations in UL41.Journal of Virology, 86:12351-61.

Schrimpf JE, Tu EM, Wang H, Wong YM, and Morrison LA. 2011. B7 costimulation molecules encoded by replication-defective, vhs-deficient HSV-1 improve vaccine-induced protection against corneal disease. PLoS ONE. 2011 6(8) e22772.

Morrison LA and DeLassus GS. 2011. Breach of the nuclear lamina during assembly of herpes simplex viruses. Nucleus 2 (4):1-6.

Cano-Monreal GL, Wylie KM, Cao F, Tavis JE, Morrison LA. Herpes simplex virus 2 UL13 protein kinase disrupts nuclear lamins. Virology. 2009 392(1):137-47.

Wylie KM, Schrimpf JE, Morrison LA. Increased eIF2alpha phosphorylation attenuates replication of herpes simplex virus 2 vhs mutants in mouse embryonic fibroblasts and correlates with reduced accumulation of the PKR antagonist ICP34.5. J Virol. 2009 83(18):9151-62.

Vagvala SP, Thebeau LG, Wilson SR, Morrison LA. Virus-encoded b7-2 costimulation molecules enhance the protective capacity of a replication-defective herpes simplex virus type 2 vaccine in immunocompetent mice. J Virol. 2009 83(2):953-60.

Morrison LA. Replication-defective virus vaccine-induced protection of mice from genital herpes simplex virus 2 requires CD4 T cells. Virology. 2008 376(1):205-10.

Korom M, Wylie KM, Morrison LA. Selective ablation of virion host shutoff protein RNase activity attenuates herpes simplex virus 2 in mice. J Virol. 2008 82(7):3642-53.

Cano-Monreal GL, Tavis JE, Morrison LA. Substrate specificity of the herpes simplex virus type 2 UL13 protein kinase. Virology. 2008 374(1):1-10.

Thebeau LG, Vagvala SP, Wong YM, Morrison LA. B7 costimulation molecules expressed from the herpes simplex virus 2 genome rescue immune induction in B7-deficient mice. J Virol. 2007 81(22):12200-9.

Duerst RJ, Morrison LA. Herpes simplex virus type 2-mediated disease is reduced in mice lacking RNase L. Virology. 2007 360(2):322-8.

Pepose JS, Keadle TL, Morrison LA. Ocular herpes simplex: changing epidemiology, emerging disease patterns, and the potential of vaccine prevention and therapy. Am J Ophthalmol. 2006 141(3):547-557. Review.



National Institutes of Health (NIAID)

Virus-encoded costimulation molecules to improve HSV-2 vaccine efficacy

An antiviral function of cellular PrP identified using HSV-1 ICP34.5 mutant virus

Saint Louis University President's Research Fund

Generation and functional domains of novel forms of the HSV-2 ICP34.5 polypeptide


National Institutes of Health (NEI)

Improving vaccine safety and efficacy to control primary HSV-1 infections

Vaccine to prevent herpes simplex virus-induced keratitis

National Institutes of Health (NIAID)

Substrate recognition motif of the HSV-2 UL13 kinase

Functional analysis of HSV-2 tegument proteins in mice

Gates Foundation

Vaccine vector to encode multiple HIV T cell epitopes

Saint Louis University President's Research Fund

Mechanisms regulating expression and modification of the herpes simplex virus 2 neurovirulence factor ICP34.5