Professor of Oncology
B.S., 1981, Biochemistry, Pennsylvania State University
Ph.D., 1988, Microbiology and Immunology, University of North Carolina at Chapel Hill
Postdoctoral research: University of North Carolina at
Chapel Hill and University of California, San Francisco
Office: 723A McArdle Laboratory
Telephone: Office - (608) 262-1260; Lab - (608) 262-2199
Email: loeb@oncology.wisc.edu
Research Interests: Molecular biology of the hepatitis B viruses
Research Description: Hepatitis B viruses (HBV) are a family of DNA viruses that can persistently infect the liver of a variety of animal hosts including humans. There is a close association between chronic HBV infection and hepatocellular carcinoma, though the mechanism of oncogenesis is not understood. Although they have a DNA genome, hepadnaviruses replicate via reverse transcription of an RNA intermediate (RNA pregenome) resulting in a relaxed circular DNA genome. The major project in our laboratory is understanding the mechanism of HBV reverse transcription. We are studying the mechanisms of RNA encapsidation, initiation and synthesis of minus-strand DNA, initiation and synthesis of plus-strand DNA, and genome circularization during plus-strand DNA synthesis. To understand the mechanism of these processes during reverse transcription we are (1) defining the cis-acting sequences involved in each step of the process, (2) determining the role of the viral trans-acting factors in each step of the process, and (3) determining the nature of the interactions between the trans-acting factors and the cis-acting elements during the process of reverse transcription.
Abraham, T. M., and Loeb, D. D. The Topology of Hepatitis B Virus Pregenomic RNA Promotes Its Replication. J. Virol., 81: 11577-11584, 2007.
Haines, K. M., and Loeb, D. D. The Sequence of the RNA Primer and the DNA Template Influence the Initiation of Plus-strand DNA Synthesis in Hepatitis B Virus. J. Mol. Biol., 370: 471-480, 2007.
Lewellyn, E. B., and Loeb, D. D. Base Pairing Between cis-Acting Sequences Contributes to Template Switching during Plus-Strand DNA Synthesis in Human Hepatitis B Virus. J. Virol., 81: 6207-6215, 2007.
Abraham, T. M., and Loeb, D. D. Base Pairing between the 5’ Half of e and a cis-Acting Sequence, F, Makes a Contribution to the Synthesis of Minus-Strand DNA for Human Hepatitis B Virus. J. Virol., 80: 4380-4387, 2006.
Habig, J. W., and Loeb, D. D. Sequence Identity of the Direct Repeats, DR1 and DR2, Contributes to the Discrimination between Primer Translocation and in Situ Priming During Replication of the Duck Hepatitis B Virus. J. Mol. Biol., 364: 32-43, 2006.
Liu, N., Ji, L., Maguire, M. L., and Loeb, D. D. cis-Acting Sequences That Contribute to the Synthesis of Relaxed-Circular DNA of Human Hepatitis B Virus. J. Virol., 78: 642-649, 2004.
Ostrow, K. M., and Loeb, D. D. Underrepresentation of the 3' Region of the Capsid Pregenomic RNA of Duck Hepatitis B Virus. J. Virol., 78: 2179-2186, 2004.
Ostrow, K. M., and Loeb, D. D. Chimeras of Duck and Heron Hepatitis B Viruses Provide Evidence for Functional Interactions between Viral Components of Pregenomic RNA Encapsidation. J. Virol., 78: 8780-8787, 2004.
Habig, J. W., and Loeb, D. D. The Conformation of the 3' End of the Minus-Strand DNA Makes Multiple Contributions to Template Switches during Plus-Strand DNA Synthesis of Duck Hepatitis B Virus. J. Virol., 77: 12401-12411, 2003.
Habig, J. W., and Loeb, D. D. Template Switches during Plus-Strand DNA Synthesis of Duck Hepatitis B Virus Are Influenced by the Base Composition of the Minus-Strand Terminal Redundancy. J. Virol., 77: 12412-12420, 2003.
Liu, N., Tian, R., and Loeb, D. D. Base Pairing Among Three cis-Acting Sequences Contributes to Template Switching during Hepadnavirus Reverse Transcription. Proc. Natl. Acad. Sci. USA, 100: 1984-1989, 2003.
Habig, J. W., and Loeb, D. D. Small DNA Hairpin Negatively Regulates In Situ Priming during Duck Hepatitis B Virus Reverse Transcription. J. Virol., 76: 980-989, 2002.
Havert, M. B., Ji, L., and Loeb, D. D. Analysis of Duck Hepatitis B Virus Reverse Transcription Indicates a Common Mechanism for the Two Template Switches during Plus-Strand DNA Synthesis. J.Virol., 76: 2763-2769, 2002.
Liu, N., Ostrow, K. M., and Loeb D. D. Identification and Characterization of a Novel Replicative Intermediate of Heron Hepatitis B Virus. Virology, 295: 348-359, 2002.
Loeb, D. D., Mack, A. A., and Tian, R. A Secondary Structure That Contains the 5' and 3' Splice Sites Suppresses Splicing of Duck Hepatitis B Virus Pregenomic RNA. J. Virol., 76: 10195-10202, 2002.
Mueller-Hill, K., and Loeb, D. D. cis-Acting Sequences 5E, M, and 3E Interact to Contribute to Primer Translocation and Circularization during Reverse Transcription of Avian Hepadnavirus DNA. J. Virol., 76: 4260-4266, 2002.
Ostrow, K. M., and Loeb, D. D. Characterization of the cis-Acting Contributions to Avian Hepadnavirus RNA Encapsidation. J. Virol., 76: 9087-9095, 2002.
Loeb, D. D., and Tian R. Mutations That Increase In Situ Priming Also Decrease Circularization for Duck Hepatitis B Virus. J. Virol., 75: 6492-6497, 2001.
