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Molecular Virology and Microbiology

Houston, Texas

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Department of Molecular Virology and Microbiology
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Janet S. Butel, Ph.D.

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Janet S. Butel, Ph.D.Distinguished Service Professor and Chair
Department of Molecular Virology & Microbiology

Research Interests

Polyomavirus Pathogenesis of Infections and Disease

The Butel laboratory is interested in the biology and molecular biology of the polyomaviruses, with a primary focus on polyomavirus SV40. Originally isolated from monkeys, SV40 is a small DNA virus that is able to transform cells in culture and induce tumors in hamsters. As a model tumor virus, SV40 has provided many fundamental insights into the molecular basis of carcinogenesis.

The large tumor antigen (T-ag) of SV40 is the major transforming protein of the virus, responsible for tumor causation in hamsters and transformation of many cell types in culture. It is a complex protein that possesses multiple functions important for replicating the viral DNA and for dysregulating cell cycle control. Sequence analysis of viral isolates has revealed differences in the structure of the noncoding viral regulatory region as well as the existence of a variable region at the C-terminus of T-ag that can classify SV40 strains into genogroups.

We have developed the Syrian golden hamster small animal model to study SV40 pathogenesis of infection and disease. Findings include the significant effect of the structure of the viral regulatory region on both oncogenic potential and vertical transmission in vivo. There was no effect on transforming activity in vitro, indicating that strain-specific factors affect virus–host interactions that are not detectable using cultured cells. Recent results from the hamster model showed the influence of SV40 microRNA on patterns of viral infection.

Research in the last several years has established that authentic SV40 can cause human infections. Findings include the fecal excretion of polyomaviruses by humans, indicating a probable fecal–oral route of transmission; the detection of SV40 in normal and malignant lymphoid-rich tissues, suggesting that lymphoid cells are important in the pathogenesis of SV40 infections; and the variable frequency of SV40-positive lymphomas in two urban populations with different demographics, emphasizing that SV40 infection and disease likely reflect population differences. The newly discovered human polyomavirus, KIV, and the human cancer virus, Merkel cell polyomavirus, are also studied.

Contact Information

Baylor College of Medicine
One Baylor Plaza
Houston, TX 77030
Room 737E

Phone: 713-798-3003


Ph.D., Baylor College of Medicine
PostDoc, Baylor College of Medicine

Awards, Appointments and Honors

1986 - Joseph L. Melnick Professor of Virology, BCM
1988 - Fellow, American Association for the Advancement of Science
1995 - Distinguished Service Professor, BCM
1996 - U.S. Patent, “Transgenic Mice Containing a Disrupted p53 Gene”
1997 - Included in “Women Pioneers in Texas Medicine” (Silverthorne, E. and Fulgham, G., Texas A&M University Press, 1997)
2002 - Recipient, 2002 Distinguished Alumnus of the Graduate School of Biomedical Sciences Award, BCM
2003 - Kansas State University Alumni Fellow
2004 - Fellow, American Academy of Microbiology
2007 - Recipient, American Association for Cancer Research–Women in Cancer Research–Charlotte Friend Memorial Lectureship
2013 – Kyle and Josephine Morrow Chair in Molecular Virology & Microbiology, Baylor College of Medicine
2013 – BioHouston, Women in Science Award

Recent Publications (PubMed)

Selected Publications

Sroller, V., Vilchez, R.A., Stewart, A.R., Wong, C. and Butel, J.S. Influence of the viral regulatory region on tumor induction by simian virus 40 in hamsters. J. Virol. 82:871–879, 2008. PMCID: PMC2224577.

Javier, R.T. and Butel, J.S. The history of tumor virology. Cancer Res. 68:7693–7706, 2008. PMCID: PMC3501656.

McNees, A.L., Vilchez, R.A., Heard, T.C., Sroller, V., Wong, C., Herron, A.J., Hamilton, M.J., Davis, W.C. and Butel, J.S. SV40 lymphomagenesis in Syrian golden hamsters. Virology 384:114–124, 2009. PMCID: PMC3648995.

Patel, N.C., Halvorson, S.J., Sroller, V., Arrington, A.S., Wong, C., Smith, E.O., Vilchez, R.A. and Butel, J.S. Viral regulatory region effects on vertical transmission of polyomavirus SV40 in hamsters. Virology 386:94–101, 2009. PMCID: PMC2668977.

Vanchiere, J.A., Abudayyeh, S., Copeland, C.M., Lu, L.B., Graham, D.Y. and Butel, J.S. Polyomavirus shedding in the stool of healthy adults. J. Clin. Microbiol. 47:2388–2391, 2009. PMCID: PMC2725650.

Toracchio, S., Kozinetz, C.A., Killen, D.E., Sheehan, A.M., Banez, E.I., Ittmann, M.M., Sroller, V. and Butel, J.S. Variable frequency of polyomavirus SV40 and herpesvirus EBV in lymphomas from two different urban population groups in Houston, Texas. J. Clin. Virol. 46:154–160, 2009. PMCID: PMC2739273.

Butel, J.S. Patterns of polyomavirus SV40 infections and associated cancers in humans: a model. Curr. Opin. Virol. 2:508–514, 2012. PMCID: PMC3422415.

Swain, J.L., Sroller, V., Wong, C., Zhang, S., Halvorson, S.J., Herron, A.J., Kozinetz, C.A. and Butel, J.S. Effects of route of inoculation and viral genetic variation on antibody responses to polyomavirus SV40 in Syrian golden hamsters. Comp. Med. 62:400–408, 2012. PMCID: PMC3472605.

Wong, C., Vilchez, R.A., Quiroz, J., Adam, E. and Butel, J.S. Ethnic differences in polyomavirus simian virus 40 seroprevalence among women in Houston, Texas. J. Infect. 66:67–74, 2013. PMCID: PMC3518614 [Available on 2014/1/1].


Lindsay Harrigal