Growth defect of domain III glycoprotein B mutants of human cytomegalovirus reverted by compensatory mutations co-localizing in post-fusion conformation
Mollik M, Rohorzka A, CHEN X, Kropff B, Eisler L, Külekci B, Puchhammer-Stöckl E, Thomas M, Görzer I (2024)
Publication Type: Journal article
Publication year: 2024
Journal
Book Volume: 15
Article Number: 01812
Journal Issue: 10
Abstract
Cell entry is a crucial step for a virus to infect a host cell. Human cytomegalovirus utilizes glycoprotein B (gB) to fuse the viral and host cell membranes upon receptor binding of gH/gL-containing complexes. Fusion is mediated by major conformational changes of gB from a metastable pre-fusion to a stable post-fusion state whereby the central trimeric coiled-coils, formed by domain (Dom)III α helices, remain structurally nearly unchanged. To better understand the role of the stable core, we individually introduced three potentially helix-breaking or one disulfide bond-breaking mutation in the DIII α3 to study different aspects of the viral behavior upon long-term culturing. Two of the three helix-breaking mutations, gB_Y494P and gB_I495P, were lethal for the virus in either fibroblasts or epithelial cells. The third substitution, gB_G493P, on the other hand, displayed a delayed replication and spread, which was more pronounced in epithelial cells, hinting at an impaired fusion. Interestingly, the disulfide bond-breaker mutation, gB_C507S, performed strikingly differently in the two cell types - lethal in epithelial cells and an atypical phenotype in fibroblasts, respectively. Replication curve analyses paired with the infection efficiency, the spread morphology, and the cell–cell fusogenicity suggest a dysregulated fusion process, which could be reverted by second-site mutations mapping predominantly to gB DomV. Our findings underline the functional importance of a stable DomIII core for a well-regulated DomV rearrangement during fusion.
Authors with CRIS profile
XIAOHAN CHEN
Lehrstuhl für Klinische und Molekulare Virologie
Marco Thomas
Institute of Clinical and Molecular Virology
Involved external institutions
Austria (AT)How to cite
APA:
Mollik, M., Rohorzka, A., CHEN, X., Kropff, B., Eisler, L., Külekci, B.,... Görzer, I. (2024). Growth defect of domain III glycoprotein B mutants of human cytomegalovirus reverted by compensatory mutations co-localizing in post-fusion conformation. mBio, 15(10). https://doi.org/10.1128/mbio.01812-24
MLA:
Mollik, Madlen, et al. "Growth defect of domain III glycoprotein B mutants of human cytomegalovirus reverted by compensatory mutations co-localizing in post-fusion conformation." mBio 15.10 (2024).
BibTeX: Download