Tetraspanin CD151 Promotes Initial Events in Human Cytomegalovirus Infection

Abstract

Human cytomegalovirus (HCMV), a betaherpesvirus, can cause life-threatening disease in immunocompromised individuals. Viral envelope glycoproteins that mediate binding to and penetration into target cells have been identified previously. In contrast, cellular proteins supporting HCMV during entry are largely unknown. In order to systematically identify host genes affecting initial steps of HCMV infection, a targeted RNA interference screen of 96 cellular genes was performed in endothelial cells by use of a virus strain expressing the full set of known glycoprotein H and L (gH/gL) complexes. The approach yielded five proviral host factors from different protein families and eight antiviral host factors, mostly growth factor receptors. The tetraspanin CD151 was uncovered as a novel proviral host factor and was analyzed further. Like endothelial cells, fibroblasts were also less susceptible to HCMV infection after CD151 depletion. Virus strains with different sets of gH/gL complexes conferring either broad or narrow cell tropism were equally impaired. Infection of CD151-depleted cells by a fluorescent virus with differentially labeled capsid and envelope proteins revealed a role of CD151 in viral penetration but not in adsorption to the cell. In conclusion, the tetraspanin CD151 has emerged as a novel host factor in HCMV entry and as a putative antiviral target. IMPORTANCEAt present, the events at the virus-cell interface and the cellular proteins involved during the HCMV entry steps are scarcely understood. In this study, several host factors with putative roles in this process were identified. The tetraspanin CD151 was discovered as a previously unrecognized proviral host factor for HCMV and was found to support viral penetration into the target cells. The findings of this study shed light on the cellular contribution during the initial steps of HCMV infection and open a new direction in HCMV research.

Hepatitis C virus enters liver cells using the CD81 receptor complex proteins calpain-5 and CBLB

“…It will be interesting to investigate whether CBL and CBLB affect influenza virus entry in a similar manner as HCV entry. Tetraspanins moreover play a role in entry and spread of HIV-1, human papillomaviruses and human cytomegalovirus [49][50][51][52]. Thus our study provides an important dataset of PPIs, which has implications beyond HCV infection.…”

Tetraspanin CD63 controls basolateral sorting of organic cation transporter 2 in renal proximal tubules

“…A characteristic property of tetraspanins appears to be the organization of other proteins into a network of multimolecular membrane microdomains, the tetraspanin-enriched microdomains, or the so-called tetraspanin web (49). Within this transmembrane network, tetraspanins associate with integrins, signaling enzymes, and other transmembrane proteins, enabling signaling, endocytosis, and trafficking processes (50)(51)(52)(53). The ability of tetraspanins to manage interactions between other proteins and to generate functional complexes suggested the term "molecular facilitators" (50,54).…”

A Luciferase Gene Driven by an Alphaherpesviral Promoter Also Responds to Immediate Early Antigens of the Betaherpesvirus HCMV, Allowing Comparative Analyses of Different Human Herpesviruses in One Reporter Cell Line

“…This suggests that expression of viral immediate early genes was sufficient for reporter gene activation in absence of infection. To exclude that components of the incoming virion or a cellular process induced by HCMV entry contribute to reporter gene activation, MV9Gs were transfected with a short interfering RNA (siRNA) directed against both viral immediate early antigens UL122 and UL123 [35,49] or a non-targeting control siRNA prior to infection with the virus strain TB40/E. The luciferase activity was reduced in UL122/123 siRNA-treated cells by 91% ± 2 SEM (Fig 3B, left).…”

“…siRNA transfections were performed as previously described [35]. A non-targeting siRNA pool (siGENOME Non-Targeting Pool #2, Thermo Fisher Scientific) and an siRNA effectively targeting the HCMV immediate early antigens 1 and 2 (UL122/123) (, Sigma-Aldrich) [35] were reversely transfected in MV9G cells in 96-well plates with Lipofectamine RNAiMAX (Life Technologies) according to the manufacturer’s instructions.…”