Differences in the effects of mutations in GP131, a guinea pig cytomegalovirus homologue of pentameric complex component UL130, on macrophage and epithelial cell infection

Abstract

As congenital cytomegalovirus (CMV) infection is the major cause of developmental abnormalities in children, the development of effective vaccines is critical to public health. Recent studies have demonstrated that the pentameric complex (Pentamer) of glycoproteins, which is required for human CMV infection of endothelial and epithelial cells, could be a potent vaccine antigen. As guinea pig CMV (GPCMV) infects congenitally and encodes homologues of all Pentamer components, GPCMV models are considered to be useful for the development of vaccine strategies. Here, to clarify the precise requirement of GP131, one of the GPCMV Pentamer components, for the infection of epithelial cells and macrophages, we prepared several mutants with a charged amino acid-to-alanine alteration in GP131 and found some differences in the effects of the mutations on the infection of the two cell types, suggesting the existence of cell type-dependent recognition or function of Pentamer in GPCMV infection.

Enhancement of guinea pig cytomegalovirus infection by two endogenously expressed components of the pentameric glycoprotein complex in epithelial cells

“…Interestingly, the D138A alteration enhanced the GPCMV infection by an additional 10-fold. There were no apparent correlations between the enhancement and the requirements for infection that we reported previously 19 (Fig. 6b).…”

“…those of the others and the mobilities of E47A and D51A in SDS-PAGE were slower than those of the wild-type (WT) and other mutated versions 19 . As shown in Fig.…”

“…3b). Combined with the fact that the GP131 gene product is incorporated in the virions 19 and the requirement for the GP131 gene in the GPCMV genome ( Fig. 1c), these results led us to speculate that the engagement of cellular receptors with virions is required for the GP131/GP133-mediated enhancement of infection.…”

“…Amino acid sequences of GP131 required for the enhancement of infection. rAds expressing GP131 with a charged amino acid-to-alanine alteration prepared previously 19 were used to identify the amino acid sequences required for the enhancement of infection. The rAd-mediated expression levels of all mutated GP131 proteins in human epithelial cell line HEK-293A were similar, while that of R152A was slightly less than Figure 2.…”

Pathogen at the Gates: Human Cytomegalovirus Entry and Cell Tropism

“…One is comprised of gH/gL bound to gO (m74) [127]; the other is made up of gH/gL bound to MCK-2, a chemokine homolog [128]. RhCMV and guinea pig CMV (GPCMV), however, appear to make use of pentameric and trimeric gH/gL complexes, and hence more closely resemble HCMV in this regard [126,[129][130][131][132][133]. The two rat CMVs, which in fact represent distinct species [134], remain to be characterized for whether a pentameric complex or one akin to MCMV gH/gL/MCK-2 is expressed in virions [135].…”