Expression Pattern and Subcellular Localization of Human Papillomavirus Minor Capsid Protein L2

Lin, Zhenhua; Yemelyanova, Anna; Gambhira, Ratish; Jagu, Subhashini; Meyers, Craig; Kirnbauer, Reinhard; Ronnett, Brigitte M.; Gravitt, Patti E.; Roden, Richard B.S.

doi:10.2353/ajpath.2009.080588

Cited by 23 publications

(21 citation statements)

References 37 publications

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“…showed no PML-like distribution, as previously described (57,58). These data suggest that HPV16 L2 and TBX2/3 also interact in vivo in the context of a naturally occurring HPV16 infection.…”

Section: Resultssupporting

confidence: 80%

“…Indeed, in previous analyses of naturally HPV-infected cells of CIN lesions, L2 showed a punctate distribution and colocalization with Sp100 in only a few cells of the intermediate layers, where L2 was weakly expressed (28). In the stratified cells of the upper layers, L2 distribution in nuclei was diffuse (28) and no longer ND10-like (58). In the tissue stainings of the present study, it was in these cells that we detected TBX2 colocalized with L2.…”

Section: Discussionsupporting

confidence: 60%

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The Transcription Factors TBX2 and TBX3 Interact with Human Papillomavirus 16 (HPV16) L2 and Repress the Long Control Region of HPVs

Schneider

Scheffer

Bund

et al. 2013

J Virol

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The minor capsid protein L2 of human papillomaviruses (HPVs) has multiple functions during the viral life cycle. Although L2 is required for effective invasion and morphogenesis, only a few cellular interaction partners are known so far. Using yeast twohybrid screening, we identified the transcription factor TBX2 as a novel interaction partner of HPV type 16 (HPV16) L2. Coimmunoprecipitations and immunofluorescence analyses confirmed the L2-TBX2 interaction and revealed that L2 also interacts with TBX3, another member of the T-box family. Transcription of the early genes during HPV infection is under the control of an upstream enhancer and early promoter region, the long control region (LCR). In promoter-reporter gene assays, we observed that TBX2 and TBX3 repress transcription from the LCR and that this effect is enhanced by L2. Repression of the HPV LCR by TBX2/3 seems to be a conserved mechanism, as it was also observed with the LCRs of different HPV types. Finally, interaction of TBX2 with the LCR was detected by chromatin immunoprecipitation, and we found a strong colocalization of L2 and TBX2 in HPV16-positive cervical intraepithelial neoplasia (CIN) I-II tissue sections. These results suggest that TBX2/3 might play a role in the regulation of HPV gene expression during the viral life cycle. Human papillomaviruses (HPVs) are small, nonenveloped viruses that infect stratified squamous epithelia of the skin or mucous membranes, inducing a variety of hyperproliferative lesions (1). The mucosotropic HPVs are classified as either low-risk or high-risk types. Lesions resulting from high-risk HPV infections (e.g., HPV type 16 [HPV16], HPV18, and HPV31) can progress to cervical and other cancers (2, 3). The icosahedral capsid of HPVs consists of 360 copies of the major capsid protein L1 (4, 5) and up to 72 copies of the minor capsid protein L2 (6). During HPV infection, L2 is required for the egress of the viral genome from endosomes (7) and for the dynein-mediated transport of the viral genome along microtubules to the nucleus (8-10). In the final steps of viral entry, L2 chaperones the viral genome to nuclear domain 10 (ND10), where initial transcription of the viral genes takes place (11). Transcription of the early viral proteins E6 and E7, representing the transforming oncogenes in high-risk HPVs, is controlled by an upstream enhancer sequence, the long control region (LCR) (also called the upstream regulatory region [URR]), which comprises the early promoter. A complex array of cellular and viral factors binds to the LCR and regulates expression of the early viral genes (12-21). The composition of the factors binding and regulating the LCR is dependent on differentiation of the host keratinocytes (22,23). In the granular cell layers, the activation of the late promoter drives the expression of the capsid proteins L1 and L2 (24-26). Besides its importance in viral entry, L2 plays a major role during virus morphogenesis. L2 reorganizes ND10 protein composition and recruits L1 into these subnuclear structures, ...

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Section: Resultssupporting

confidence: 80%

Section: Discussionsupporting

confidence: 60%

The Transcription Factors TBX2 and TBX3 Interact with Human Papillomavirus 16 (HPV16) L2 and Repress the Long Control Region of HPVs

Schneider

Scheffer

Bund

et al. 2013

J Virol

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“…5D), diffuse nuclear localization (data not shown), or cytoplasmic localization of L2 (Fig. 5F) due to different expression levels and the diverse localization signals of L2 as described earlier (70)(71)(72). In cotransfected cells, the cellular localization patterns of OBSL1 and L2 changed and both proteins were strongly colocalized in the cytoplasm (Fig.…”

Section: Hpv16 L2 Forms a Complex With Obsl1supporting

confidence: 61%

The Cytoskeletal Adaptor Obscurin-Like 1 Interacts with the Human Papillomavirus 16 (HPV16) Capsid Protein L2 and Is Required for HPV16 Endocytosis

Wüstenhagen

Hampe

Boukhallouk

et al. 2016

J Virol

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The human papillomavirus (HPV) capsid protein L2 is essential for viral entry. To gain a deeper understanding of the role of L2, we searched for novel cellular L2-interacting proteins. A yeast two-hybrid analysis uncovered the actin-depolymerizing factor gelsolin, the membrane glycoprotein dysadherin, the centrosomal protein 68 (Cep68), and the cytoskeletal adaptor protein obscurin-like 1 protein (OBSL1) as putative L2 binding molecules. Pseudovirus (PsV) infection assays identified OBSL1 as a host factor required for gene transduction by three oncogenic human papillomavirus types, HPV16, HPV18, and HPV31. In addition, we detected OBSL1 expression in cervical tissue sections and noted the involvement of OBSL1 during gene transduction of primary keratinocytes by HPV16 PsV. Complex formation of HPV16 L2 with OBSL1 was demonstrated in coimmunofluorescence and coimmunoprecipitation studies after overexpression of L2 or after PsV exposure. We observed a strong colocalization of OBSL1 with HPV16 PsV and tetraspanin CD151 at the plasma membrane, suggesting a role for OBSL1 in viral endocytosis. Indeed, viral entry assays exhibited a reduction of viral endocytosis in OBSL1-depleted cells. Our results suggest OBSL1 as a novel L2-interacting protein and endocytosis factor in HPV infection. IMPORTANCEHuman papillomaviruses infect mucosal and cutaneous epithelia, and the high-risk HPV types account for 5% of cancer cases worldwide. As recently discovered, HPV entry occurs by a clathrin-, caveolin-, and dynamin-independent endocytosis via tetraspanin-enriched microdomains. At present, the cellular proteins involved in the underlying mechanism of this type of endocytosis are under investigation. In this study, the cytoskeletal adaptor OBSL1 was discovered as a previously unrecognized interaction partner of the minor capsid protein L2 and was identified as a proviral host factor required for HPV16 endocytosis into target cells. The findings of this study advance the understanding of a so far less well-characterized endocytic pathway that is used by oncogenic HPV subtypes. Human papillomaviruses (HPVs) are small, nonenveloped DNA viruses that infect dividing basal keratinocytes of skin and mucosa via microlesions of the tissue. HPV is capable of inducing benign epithelial warts on the skin and mucosa, and infection with a high-risk HPV type may cause cervical and other anogenital and oropharyngeal cancers (1, 2). Cervical cancer is the third most common cancer in women worldwide and is associated with HPV infection, more precisely with high-risk HPV types such as HPV16, HPV18, and HPV31 (3). HPV is composed of a viral capsid with the major capsid protein L1, the minor capsid protein L2, and the viral genome. One icosahedral capsid contains 360 copies of L1, which can self-assemble to 72 pentamers, and up to 72 copies of the minor capsid protein L2, located inside the L1 shell (4-6). The capsid proteins L1 and L2 are key players in early events of infection, such as virus binding at the plasma membrane, cell entry, and t...

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“…During the productive phase of infection the expression and nuclear import of L2 in natural lesions precede expression and nuclear translocation of L1 major capsid protein (Florin et al, 2002). The L2 protein has a diffuse nuclear localization in cervical intraepithelial neoplasia lesions and HPV16-transduced organotypic cultures (Lin et al, 2009). We have previously determined that HPV16 L2 contains two nuclear localization signals (NLSs), one at the amino-terminus (nNLS) and the other at the carboxy-terminus (cNLS).…”

Section: Introductionmentioning

confidence: 99%

The high risk HPV16 L2 minor capsid protein has multiple transport signals that mediate its nucleocytoplasmic traffic

et al. 2012

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In this study we examined the transport signals contributing to HPV16 L2 nucleocytoplasmic traffic using confocal microscopy analysis of enhanced green fluorescent protein – L2 (EGFP-L2) fusions expressed in HeLa cells. We confirmed that both nuclear localization signals (NLSs), the nNLS (1MRHKRSAKRTKR12) and cNLS (456RKRRKR461), previously characterized in vitro (Darshan et al., 2004), function independently in vivo. We discovered that a middle region rich in arginine residues (296SRRTGIRYSRIGNKQTLRTRS316) functions as a nuclear retention sequence (NRS), as mutagenesis of critical arginine residues within this NRS reduced the fraction of L2 in the nucleus despite the presence of both NLSs. Significantly, the infectivity of HPV16 pseudoviruses containing either RR297AA or RR297EE within the L2 NRS was strongly reduced both in HaCaT cells and in a murine challenge model. Experiments using Ratjadone A nuclear export inhibitor and mutation-localization analysis lead to the discovery of a leucine-rich nuclear export signal (462LPYFFSDVSL) mediating 16L2 nuclear export. These data indicate that HPV16 L2 nucleocytoplasmic traffic is dependent on multiple functional transport signals.

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Expression Pattern and Subcellular Localization of Human Papillomavirus Minor Capsid Protein L2

Cited by 23 publications

References 37 publications

The Transcription Factors TBX2 and TBX3 Interact with Human Papillomavirus 16 (HPV16) L2 and Repress the Long Control Region of HPVs

The Transcription Factors TBX2 and TBX3 Interact with Human Papillomavirus 16 (HPV16) L2 and Repress the Long Control Region of HPVs

The Cytoskeletal Adaptor Obscurin-Like 1 Interacts with the Human Papillomavirus 16 (HPV16) Capsid Protein L2 and Is Required for HPV16 Endocytosis

The high risk HPV16 L2 minor capsid protein has multiple transport signals that mediate its nucleocytoplasmic traffic

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