Mutagenesis of Human Cytomegalovirus Glycoprotein L Disproportionately Disrupts gH/gL/gO over gH/gL/pUL128-131
- Univ. of Montana, Missoula, MT (United States)
Herein, cell-free and cell-to-cell spread of herpesviruses involves a core fusion apparatus comprised of the fusion protein glycoprotein B (gB) and the regulatory factor gH/gL. The human cytomegalovirus (HCMV) gH/gL/gO and gH/gL/pUL128-131 facilitate spread in different cell types. The gO and pUL128-131 components bind distinct receptors, but how the gH/gL portions of the complexes functionally compare is not understood. We previously characterized a panel of gL mutants by transient expression and showed that many were impaired for gH/gL-gB-dependent cell-cell fusion but were still able to form gH/gL/pUL128-131 and induce receptor interference. Here, the gL mutants were engineered into the HCMV BAC clones TB40/e-BAC4 (TB), TR, and Merlin (ME), which differ in their utilization of the two complexes for entry and spread. Several of the gL mutations disproportionately impacted gH/gL/gO-dependent entry and spread over gH/gL/pUL128-131 processes. The effects of some mutants could be explained by impaired gH/gL/gO assembly, but other mutants impacted gH/gL/gO function. Soluble gH/gL/gO containing the L201 mutant failed to block HCMV infection despite unimpaired binding to PDGFRα, indicating the existence of other important gH/gL/gO receptors. Another mutant (L139) enhanced the gH/gL/gO-dependent cell-free spread of TR, suggesting a “hyperactive” gH/gL/gO. Recently published crystallography and cryo-electron microscopy studies suggest structural conservation of the gH/gL underlying gH/gL/gO and gH/gL/pUL128-131. However, our data suggest important differences in the gH/gL of the two complexes and support a model in which gH/gL/gO can provide an activation signal for gB.
- Research Organization:
- Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)
- Sponsoring Organization:
- USDOE; National Institutes of Health (NIH); e German Research Foundation (DFG)
- Grant/Contract Number:
- AC05-76RL01830
- OSTI ID:
- 1922084
- Report Number(s):
- PNNL-SA-166126
- Journal Information:
- Journal of Virology, Journal Name: Journal of Virology Journal Issue: 17 Vol. 95; ISSN 0022-538X
- Publisher:
- American Society for MicrobiologyCopyright Statement
- Country of Publication:
- United States
- Language:
- English
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