Effect of pH on the structure and function of La Crosse virus

The La Crosse (LAC) virus is a member of the California encephalitis group of bunyaviridae (Porterfield et al., 1975 and 1976). It is one of an envelope virus and this virus under acidic conditions (below pH 6.3) has been demonstrated to result in cell-to-cell fusion (Gonzalez-Scarano, 1984). The LAC virus is also capable of forming virus-to-virus fusion particles. The focus of this thesis is the analysis of the structure and function of this virus-to-virus fusion by cryo-electron microscopy at different pH and temperatures. The results of this study provide the basis for further study of the structure and function of the LAC virus. The virus-to-virus fusion event shows a dependence on both pH and temperature. The frequency of the fusion event increases with an elevation in temperature (in the range 4 to 37°C) and with a decrease in pH from 7.3 to 5.4. The process of virus-to-virus fusion gives rise to the formation budding to a chain of fused viruses