Seoul virus is a hantavirus that causes hemorrhagic fever with renal syndrome (HFRS). The virion has a tripartite (S, M, and L) negative-stranded RNA genome, which is characteristic of the familyBunyaviridae. However, the molecular basis of virus replication is not well known. We established a Northern blot hybridization (NB) procedure using digoxygenin-labeled RNA probes, to quantitate the hantaviral plus- and minus-strand RNAs separately. Virus RNA replication was analyzed in infected Vero E6 cells. When the Vero E6 cells were infected with Seoul virus strain KI-83-262 (KI) at m.o.i. = 0.25, the plus-strand RNA was detected within 1 h post-infection (hpi), and the minus-strand RNA was detected subsequently. Using laser confocal microscopy, the nucleocapsid protein (NP) was detected within 2 hpi, and accumulated as scattered granules in the cytoplasm until 24 hpi. In contrast, the G2 protein first appeared at 8 hpi, was immediately transported to the Golgi, and accumulated in the Golgi until 24 hpi. Infectious virus particles were released into the medium at 24 h hpi. These findings indicate that hantavirus RNA replication starts with the appearance of NP at 2 hpi, glycoproteins then accumulate gradually in the Golgi, and virion formation is initiated once the viral RNAs and proteins have accumulated.

Authors and Affiliations

1. Laboratory of Public Health, Department of Environmental Veterinary Sciences, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, Japan, , , , , , JP

   H. Kariwa, H. Tanabe, T. Mizutani, K. Lokugamage, N. Lokugamage, M. A. Iwasa, T. Hagiya, K. Araki & I. Takashima

2. Laboratory of Anatomy, Department of Biomedical Sciences, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, Japan, , , , , , JP

   Y. Kon

3. Institute of Animal Experimentation, School of Medicine, Hokkaido University, Sapporo, Japan, , , , , , JP

   K. Yoshimatsu & J. Arikawa

Received October 10, 2002; accepted April 25, 2003Published online July 17, 2003

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