Differential processing of sindbis virus glycoprotein PE2 in cultured vertebrate and arthropod cells
HW Heidner, TA Knott, RE Johnston - Journal of Virology, 1996 - Am Soc Microbiol
HW Heidner, TA Knott, RE Johnston
Journal of Virology, 1996•Am Soc MicrobiolA step in the maturation of Sindbis virus glycoproteins is the cleavage of the precursor
glycoprotein PE2 into E3 and E2 by furin or a furin-like host cell protease. The results
presented here suggest that PE2 cleavage is an obligatory event for Sindbis virus
maturation in C6/36 cells and demonstrate that certain mutants display a cell-specific PE2
cleavage phenotype. We previously have described Sindbis virus variants which fail to
cleave PE2 because of incorporation of a signal for N-linked glycosylation immediately …
glycoprotein PE2 into E3 and E2 by furin or a furin-like host cell protease. The results
presented here suggest that PE2 cleavage is an obligatory event for Sindbis virus
maturation in C6/36 cells and demonstrate that certain mutants display a cell-specific PE2
cleavage phenotype. We previously have described Sindbis virus variants which fail to
cleave PE2 because of incorporation of a signal for N-linked glycosylation immediately …
A step in the maturation of Sindbis virus glycoproteins is the cleavage of the precursor glycoprotein PE2 into E3 and E2 by furin or a furin-like host cell protease. The results presented here suggest that PE2 cleavage is an obligatory event for Sindbis virus maturation in C6/36 cells and demonstrate that certain mutants display a cell-specific PE2 cleavage phenotype. We previously have described Sindbis virus variants which fail to cleave PE2 because of incorporation of a signal for N-linked glycosylation immediately adjacent to the PE2 cleavage site but are viable in BHK-21 cells by virtue of an additional mutation at E2 216 or E2 191 (TRSB-NE2G216 and TRSB-NE2T191, respectively) (H. W. Heidner, K. L. McKnight, N. L. Davis, and R. E. Johnston, J. Virol. 68:2683-2692, 1994). Other viable PE2 cleavage-defective mutants were constructed by substituting the parental residue at E2 position 1 (Arg), with Leu or Val (TRSB-E2L1 and TRSB-E2V1, respectively) (H.W. Heidner and R. E. Johnston, J. Virol. 68:8064-8070, 1994). When grown in BHK-21 cells, all four of these viruses replicated normally and incorporated PE2 in place of E2 in released virions. However, growth of TRSB-NE2G216 and TRSB-NE2T191 was severely restricted in cultured arthropod cells (C6/36 cells). Analysis of infected C6/36 cells by flow cytometry demonstrated that the restricted growth of TRSB-NE2G216 and TRSB-NE2T191 was not due to an impaired ability to initiate infection. In addition, TRSB-NE2G216 and TRSB-NE2T191 remained growth restricted in C6/36 cells following introduction of in vitro transcriptions by electroporation. In contrast, the PE2 cleavage defect of TRSB-E2L1 and TRSB-E2V1 was cell type specific. In C6/36 cells, the majority of PE2 was converted to E2, and these viruses replicated normally in C6/36 cells. These results demonstrated a consistent link between expression of a PE2 cleavage defect and restricted growth in C6/36 cells and suggest that cleavage of PE2 is required for maturation of Sindbis virus late in infection of C6/36 cells.
American Society for Microbiology