Wei-Shau  Hu, Ph.D.
Wei-Shau Hu, Ph.D.
Senior Investigator
Head, Viral Recombination Section

Center for Cancer Research
National Cancer Institute

Building 535, Room 336
Frederick, MD 21702-1201
301-846-1250

Dr. Hu is widely recognized as a key authority on retroviral recombination, RNA packaging, and virus assembly. Her innovations in combining molecular biology and biochemical approaches with state-of-the-art microscopy techniques for single-virion particle analysis have led to significant advancements in HIV molecular virology research. Under Dr. Hu’s direction, the Viral Recombination Section investigates multiple aspects of the retroviral life cycle that affect the transfer of viral genetic information. These studies have profound implications for questions that are fundamentally important to HIV replication, which can be used to generate new strategies to block the spread of HIV.

Areas of Expertise
1) HIV pathogenesis, 2) retroviral replication, 3) RNA packaging and virus assembly, 4) virology, 5) molecular biology, 6) infectious diseases

Retroviral RNA Trafficking, RNA Packaging, Virus Assembly, and Replication

We study how retroviruses transfer genetic information to the next generation. HIV-1 packages two copies of full-length viral RNA into a particle. Upon infecting a new host cell, virion RNA is used as the template to generate viral DNA, which integrates into the host chromosome to form a provirus. We study several aspects of the viral replication cycles that affect the transfer of viral genetic information, including the transport and trafficking of the viral RNA, packaging of the viral RNA genome, virus assembly, and reverse transcription. We use molecular biology and biochemical approaches in combination with state-of-the-art microscopy techniques to study these topics.

Retroviral RNA packaging and virus assembly. In order to generate infectious viruses, HIV-1 must encapsidate full-length unspliced RNAs into its particle. To study HIV-1 RNA packaging, we have developed a novel assay to directly visualize viral RNA in the particles at single-RNA-molecule sensitivity. This assay reveals that most HIV-1 particles contain two copies of full-length viral RNA. Although it is known that retroviral RNAs that are packaged into particles are dimeric, standard biochemical assays cannot determine the number of RNA molecules in one particle; our results provide evidence to support the long-standing assumption that two RNA molecules (one dimer) are packaged into a particle. To better understand the mechanisms of RNA packaging, we have performed genetic, biochemical, and imaging analyses to show that HIV-1 RNA uses base-pairing of the dimerization initiation signal sequence to select its copackaged RNA partner, and this process occurs in the cytoplasm of the producer cell prior to RNA packaging into particles. We study the mechanisms that HIV-1 uses to regulate which and how many RNAs are packaged. Additionally, we study the interactions between viral Gag protein and full-length RNA that lead to the encapsidation of the viral genome during virus assembly.

Retroviral RNA trafficking. Full-length HIV-1 RNA needs to traffic to specific subcellular locations to carry out its functions, including serving as a template for Gag/Gag-Pol translation and as a genome in the newly assembled virion. The functions of the viral RNA and the translated proteins can be affected when RNA is targeted to incorrect locations in the cells. Furthermore, the export pathway used by HIV-1 RNA exiting the nucleus can affect the RNA:RNA interactions that are required for dimerization and copackaging. Using our newly developed imaging tools, we study HIV-1 RNA transport and its relation to the function of viral RNAs. These experiments will provide an understanding of aspects of HIV-1 replication that we currently know very little about and will allow us to better understand how HIV-1 uses the cellular machinery to traffic its macromolecules.

Reverse transcription and recombination. Recombination plays an important role in HIV replication and evolution. For example, many of the primary isolates of HIV are recombinants, and recombination can assort mutations to generate variants that escape host immune responses or are resistant to multidrug treatment protocols. Recombination of HIV-1 occurs during reverse transcription, using information in the two RNAs to produce a hybrid DNA. Therefore, phenotypically different recombinants are generated from viruses containing two copies of different RNAs. Only cells that are doubly infected can produce virions containing two different RNAs. To better understand interactions in HIV-1 populations, we study the dynamics of double infection, the frequency of recombination, and the mechanism of reverse transcription.

Scientific Focus Areas:
Microbiology and Infectious Diseases, Molecular Biology and Biochemistry, Virology
Selected Key Publications
  1. Nikolaitchik O, Dilley K, Fu W, Gorelick R, Tai S, Soheilian F, Ptak R, Nagashima K, Pathak V, Hu W.
    PLoS Pathog. 9(3): e1003249, 2013. [ Journal Article ]
  2. Moore MD, Nikolaitchik OA, Chen J, Hammarskjöld ML, Rekosh D, Hu WS.
    PLoS Pathog. 5: e1000627, 2009. [ Journal Article ]
  3. Chen J, Nikolaitchik O, Singh J, Wright A, Bencsics CE, Coffin JM, Ni N, Lockett S, Pathak VK, Hu WS.
    Proc Natl Acad Sci U S A. 106: 13535-40, 2009. [ Journal Article ]
  4. Boyko V, Leavitt M, Gorelick R, Fu W, Nikolaitchik O, Pathak VK, Nagashima K, Hu WS.
    Mol Cell. 23: 281-7, 2006. [ Journal Article ]
  5. Chin MP, Rhodes TD, Chen J, Fu W, Hu WS.
    Proc Natl Acad Sci U S A. 102: 9002-9007, 2005. [ Journal Article ]

Dr. Wei-Shau Hu received her Ph.D. in Genetics from the University of California, Davis, in 1987. She studied the mechanisms of DNA recombination that lead to human a-thalassemia in Dr. James Shen's laboratory. Under Dr. Howard Temin's guidance, she studied the mechanisms of retroviral recombination as a postdoctoral fellow at the University of Wisconsin. In 1991, Dr. Hu joined the faculty of West Virginia University as an Assistant Professor in the Department of Microbiology and Immunobiology and the Mary Babb Randolph Cancer Center. She was promoted to Associate Professor with tenure in 1998. In 1999, she joined the National Cancer Institute as Senior Investigator and Head of the Viral Recombination Section in the HIV Drug Resistance Program, Center for Cancer Research. Dr. Hu was an organizer of the 2009 Cold Spring Harbor Retroviruses conference. She currently serves as the Frederick representative of Women Science Advisors for the Center for Cancer Research, a member of the Special Review Panel and Study Section of the National Institutes of Health extramural grant funding programs, and a member of the Center for Cancer Research promotion review panel. In 2012, she was the recipient of one of the five grants that the U.S.-Russia Joint Working Group on Biomedical Research Cooperation awarded to National Cancer Institute intramural investigators for their highly meritorious research applications; Dr. Hu's application was focused on understanding the impact of HIV-1 recombination and cell-to-cell transmission on vaccine development and chemoprevention strategy.

Name Position
Jianbo Chen Ph.D. Staff Scientist
Kari Ann Dilley Ph.D. Special Volunteer
Malika Kuzembayeva Ph.D. Postdoctoral Fellow (Visiting)
Yang Liu Ph.D. Postdoctoral Fellow (Visiting)
Olga A. Nikolaitchik Ph.D. Research Biologist
Sergey Plisov B.S. Postbaccalaureate Fellow
Sheikh Abdul Rahman Ph.D. Postdoctoral Fellow (Visiting)
Steven Santos Ph.D. Postdoctoral Fellow (CRTA)
Luca Sardo Ph.D. Postdoctoral Fellow (Visiting)
Chijioke Umunnakwe Ph.D. Postdoctoral Fellow (Visiting)

Summary

Dr. Hu is widely recognized as a key authority on retroviral recombination, RNA packaging, and virus assembly. Her innovations in combining molecular biology and biochemical approaches with state-of-the-art microscopy techniques for single-virion particle analysis have led to significant advancements in HIV molecular virology research. Under Dr. Hu’s direction, the Viral Recombination Section investigates multiple aspects of the retroviral life cycle that affect the transfer of viral genetic information. These studies have profound implications for questions that are fundamentally important to HIV replication, which can be used to generate new strategies to block the spread of HIV.

Areas of Expertise
1) HIV pathogenesis, 2) retroviral replication, 3) RNA packaging and virus assembly, 4) virology, 5) molecular biology, 6) infectious diseases

Research

Retroviral RNA Trafficking, RNA Packaging, Virus Assembly, and Replication

We study how retroviruses transfer genetic information to the next generation. HIV-1 packages two copies of full-length viral RNA into a particle. Upon infecting a new host cell, virion RNA is used as the template to generate viral DNA, which integrates into the host chromosome to form a provirus. We study several aspects of the viral replication cycles that affect the transfer of viral genetic information, including the transport and trafficking of the viral RNA, packaging of the viral RNA genome, virus assembly, and reverse transcription. We use molecular biology and biochemical approaches in combination with state-of-the-art microscopy techniques to study these topics.

Retroviral RNA packaging and virus assembly. In order to generate infectious viruses, HIV-1 must encapsidate full-length unspliced RNAs into its particle. To study HIV-1 RNA packaging, we have developed a novel assay to directly visualize viral RNA in the particles at single-RNA-molecule sensitivity. This assay reveals that most HIV-1 particles contain two copies of full-length viral RNA. Although it is known that retroviral RNAs that are packaged into particles are dimeric, standard biochemical assays cannot determine the number of RNA molecules in one particle; our results provide evidence to support the long-standing assumption that two RNA molecules (one dimer) are packaged into a particle. To better understand the mechanisms of RNA packaging, we have performed genetic, biochemical, and imaging analyses to show that HIV-1 RNA uses base-pairing of the dimerization initiation signal sequence to select its copackaged RNA partner, and this process occurs in the cytoplasm of the producer cell prior to RNA packaging into particles. We study the mechanisms that HIV-1 uses to regulate which and how many RNAs are packaged. Additionally, we study the interactions between viral Gag protein and full-length RNA that lead to the encapsidation of the viral genome during virus assembly.

Retroviral RNA trafficking. Full-length HIV-1 RNA needs to traffic to specific subcellular locations to carry out its functions, including serving as a template for Gag/Gag-Pol translation and as a genome in the newly assembled virion. The functions of the viral RNA and the translated proteins can be affected when RNA is targeted to incorrect locations in the cells. Furthermore, the export pathway used by HIV-1 RNA exiting the nucleus can affect the RNA:RNA interactions that are required for dimerization and copackaging. Using our newly developed imaging tools, we study HIV-1 RNA transport and its relation to the function of viral RNAs. These experiments will provide an understanding of aspects of HIV-1 replication that we currently know very little about and will allow us to better understand how HIV-1 uses the cellular machinery to traffic its macromolecules.

Reverse transcription and recombination. Recombination plays an important role in HIV replication and evolution. For example, many of the primary isolates of HIV are recombinants, and recombination can assort mutations to generate variants that escape host immune responses or are resistant to multidrug treatment protocols. Recombination of HIV-1 occurs during reverse transcription, using information in the two RNAs to produce a hybrid DNA. Therefore, phenotypically different recombinants are generated from viruses containing two copies of different RNAs. Only cells that are doubly infected can produce virions containing two different RNAs. To better understand interactions in HIV-1 populations, we study the dynamics of double infection, the frequency of recombination, and the mechanism of reverse transcription.

Scientific Focus Areas:
Microbiology and Infectious Diseases, Molecular Biology and Biochemistry, Virology

Publications

Selected Key Publications
  1. Nikolaitchik O, Dilley K, Fu W, Gorelick R, Tai S, Soheilian F, Ptak R, Nagashima K, Pathak V, Hu W.
    PLoS Pathog. 9(3): e1003249, 2013. [ Journal Article ]
  2. Moore MD, Nikolaitchik OA, Chen J, Hammarskjöld ML, Rekosh D, Hu WS.
    PLoS Pathog. 5: e1000627, 2009. [ Journal Article ]
  3. Chen J, Nikolaitchik O, Singh J, Wright A, Bencsics CE, Coffin JM, Ni N, Lockett S, Pathak VK, Hu WS.
    Proc Natl Acad Sci U S A. 106: 13535-40, 2009. [ Journal Article ]
  4. Boyko V, Leavitt M, Gorelick R, Fu W, Nikolaitchik O, Pathak VK, Nagashima K, Hu WS.
    Mol Cell. 23: 281-7, 2006. [ Journal Article ]
  5. Chin MP, Rhodes TD, Chen J, Fu W, Hu WS.
    Proc Natl Acad Sci U S A. 102: 9002-9007, 2005. [ Journal Article ]

Biography

Dr. Wei-Shau Hu received her Ph.D. in Genetics from the University of California, Davis, in 1987. She studied the mechanisms of DNA recombination that lead to human a-thalassemia in Dr. James Shen's laboratory. Under Dr. Howard Temin's guidance, she studied the mechanisms of retroviral recombination as a postdoctoral fellow at the University of Wisconsin. In 1991, Dr. Hu joined the faculty of West Virginia University as an Assistant Professor in the Department of Microbiology and Immunobiology and the Mary Babb Randolph Cancer Center. She was promoted to Associate Professor with tenure in 1998. In 1999, she joined the National Cancer Institute as Senior Investigator and Head of the Viral Recombination Section in the HIV Drug Resistance Program, Center for Cancer Research. Dr. Hu was an organizer of the 2009 Cold Spring Harbor Retroviruses conference. She currently serves as the Frederick representative of Women Science Advisors for the Center for Cancer Research, a member of the Special Review Panel and Study Section of the National Institutes of Health extramural grant funding programs, and a member of the Center for Cancer Research promotion review panel. In 2012, she was the recipient of one of the five grants that the U.S.-Russia Joint Working Group on Biomedical Research Cooperation awarded to National Cancer Institute intramural investigators for their highly meritorious research applications; Dr. Hu's application was focused on understanding the impact of HIV-1 recombination and cell-to-cell transmission on vaccine development and chemoprevention strategy.

Team

Name Position
Jianbo Chen Ph.D. Staff Scientist
Kari Ann Dilley Ph.D. Special Volunteer
Malika Kuzembayeva Ph.D. Postdoctoral Fellow (Visiting)
Yang Liu Ph.D. Postdoctoral Fellow (Visiting)
Olga A. Nikolaitchik Ph.D. Research Biologist
Sergey Plisov B.S. Postbaccalaureate Fellow
Sheikh Abdul Rahman Ph.D. Postdoctoral Fellow (Visiting)
Steven Santos Ph.D. Postdoctoral Fellow (CRTA)
Luca Sardo Ph.D. Postdoctoral Fellow (Visiting)
Chijioke Umunnakwe Ph.D. Postdoctoral Fellow (Visiting)