Objectives: DNAJ/HSP40 is an evolutionarily conserved family of proteins bearing various functions. Historically, it has been emphasized that HSP40/DNAJ family proteins play a positive role in infection of various viruses. We identified DNAJ/HSP40B6 as a potential negative regulator of HIV-1 replication in our genetic screens. In this study, we investigated the functional interactions between HIV-1 and HSP40 family members.
Design: We took genetic and comparative virology approaches to expand the primary observation.
Methods: Multiple HSP40/DNAJ proteins were tested for their ability to inhibit replication of adenovirus, herpes simplex virus type 1, HIV-1, and vaccinia virus. The mechanism of inhibition was investigated by using HSP40/DNAJ mutants and measuring the efficiencies of each viral replication steps.
Results: HSP40A1, B1, B6, and C5, but not C3, were found to be able to limit HIV-1 production. This effect was specific to HIV-1 for such effects were not detected in adenovirus, herpes simplex virus type 1, and vaccinia virus. Genetic analyses suggested that the conserved DNAJ domain was responsible for the inhibition of HIV-1 production through which HSP40 regulates HSP70 ATPase activity. Interestingly, HSP40s lowered the levels of steady-state viral messenger RNA. This was not attributed to the inhibition of Tat/long terminal repeat-driven transcription but the downregulation of Rev expression.
Conclusions: This is the first report providing evidence that HSP70-HSP40 complex confers an innate resistance specific to HIV-1. For their interferon-inducible nature, HSP40 family members should account for the anti-HIV-1 function of interferon.
*AIDS Research Center, National Institute of Infectious Diseases, Tokyo, Japan;
†Kitasato Institute for Life Sciences, Graduate School of Infection Control, Kitasato University, Tokyo Japan; and
‡Department of Infectious Diseases, Virology Division, Osaka Prefectural Institute of Public Health, Osaka, Japan (Dr Urano is now with the Virus-Cell Interaction Section, HIV Drug Resistance Program, National Cancer Institute, Frederick, MD).
Correspondence to: Jun Komano, MD, PhD, Osaka Prefectural Institute of Public Health, Department of Infectious Diseases, Virology Division, 3-69, Nakamachi, 1-chome, Higashinari-ku, Osaka 537-0025, Japan (e-mail: email@example.com).
Supported by the Japan Health Science Foundation; the Japanese Ministry of Health, Labor, and Welfare and the Japanese Ministry of Education, Culture, Sports, Science and Technology.
E.U., Y.M., and J.K. designed and performed the experiments and interpreted the data. J.K. and E.U. wrote the manuscript.
The authors have no conflicts of interest to disclose.
Received December 21, 2012
Accepted May 01, 2013