Identification of DNA-protein interactions and enhancer activity at the 5' end of the upstream regulatory region in human papillomavirus type 11

We have examined the 5' end of the noncoding region of the genome of a human papillomavirus, HPV-11, for regulatory elements using permissive host cells. This region of unknown function in the upstream regulatory region (URR) is known to have unusual DNA structure and frequently contains rearrangements which are associated with some more virulent isolates. This 5' 269-bp fragment was found to exhibit both specific DNA-protein binding using laryngeal papilloma protein extracts and enhancer activity in normal and papillomatous primary laryngeal cells. The viral DNA flanks the L1 open reading frame and does not contain the viral E2 binding site. Three distinct protein binding sites are contained in a 50-bp region of the fragment. This fragment, as a whole, functions as an enhancer in primary laryngeal and papilloma cells when ligated to the SV40 promoter and SV40 T-antigen gene. We conclude that this part of the noncoding region of the papillomaviruses has elements characteristic of regulatory elements in cells permissive for infection by these viruses.     

Duplication of enhancer sequences in human papillomavirus 6 from condylomas of the mamilla

Human papillomavirus (HPV) 6 usually induces tumors of the genital, oral, or laryngeal mucosa. An HPV 6-related DNA of 8.2 kb was detected in an extrachromosomal state in atypically located condylomas of the mamilla and was molecularly cloned. The identity of the cloned HPV DNA and the viral DNA in the biopsy was confirmed by comparative Pstl cleavage analysis, which showed typical HPV 6 DNA fragment patterns except for 0.2-kb larger B fragments. Sequencing revealed an exact 236-bp duplication encompassing nucleotides 7681 to 7896 of HPV 6b. This tandem repeat is just upstream from the putative early promoter and contains a 20-bp insertion at position 7720, which constitutes an enhancer element described by R. F. Rando, W. D. Lancaster, P. Han, and C. Lopez (Virology 155, 545-556, 1986). A Hinfl-Pstl fragment containing the whole duplication was cloned into an enhancer-dependent CAT expression vector and led to three- to sevenfold increased CAT activity when compared with the monomeric sequence in C127 cells and BPV1 transformed C127 cells. This indicates that the duplication within the HPV 6 isolate from the mamilla may influence early gene expression and possibly tissue tropism.     

Glucocorticoid-dependent transformation by human papillomavirus type 16 E7 coding and 3' noncoding sequences.

The establishment of transformation of primary rodent cells by human papillomavirus (HPV) type 16 DNA requires glucocorticoid hormones (Pater et al., Nature 335, 832-835, 1988). Here we provide evidence by mutational analysis that, in the context of the hormone-regulated HPV 16 promoter/enhancer, the only protein coding sequences of HPV 16 required are those of the E7 gene. Moreover, additional sequences adjacent to the 3' end of E7 coding sequences are also essential for the establishment of the transformed phenotype. Splice donor sites, especially an E7 ORF 3' proximal one, are implicated for this cis-acting function, since specific deletion mutations of these splice sites greatly or completely reduced the frequency of transformation and the level of E7 RNA.     

PCR analysis of the upstream regulatory region of human papillomavirus genomes in cervical intraepithelial neoplasia and cervical carcinoma.

AIMS--To test whether human papillomavirus (HPV) variants with large scale sequence alterations to the upstream regulatory region are present in cervical intraepithelial neoplasias (CIN) and cervical carcinomas. METHODS--New PCR based assays were designed specifically to detect large scale insertion/deletion alterations in the upstream regulatory region of HPV 16 and 18. The assays were applied to 24 cases of CIN and 34 cases of cervical carcinoma previously shown to contain these two high risk HPV types. RESULTS--No large scale sequence alterations were found in any of the HPV containing CIN or carcinomas. CONCLUSIONS--These negative findings suggest that major upstream regulatory region variants of HPV 16 and 18 do not contribute to most cervical neoplasms.     

The human papillomavirus type 16 E7 protein binds human interferon regulatory factor-9 via a novel PEST domain required for transformation.

It is critical that viruses are able to avoid the antiviral activities of interferon (IFN). We have shown previously that the human papillomavirus (HPV) is able to avoid IFN-alpha via interaction of the HPV-16 E7 protein with IFN regulatory factor-9 (IRF-9). Here, we investigated the details of the interaction using HPV-16 E7 peptide mapping to show that IRF-9 binds HPV-16 E7 in a domain encompassing amino acids 25-36. A closer examination of this region indicates this is a novel proline, glutamate, serine, and threonine-rich (PEST) domain, with a PEST score of 8.74. We have also mapped the region of interaction within IRF-9 and found that amino acids 354-393 play an important role in binding to HPV-16 E7. This region of IRF-9 encompasses the IRF association domain (IAD), a region important for protein-protein interaction central to IRF function. Finally, we used alanine-scanning mutagenesis to determine if E7-IRF-9 interaction was important for E7-mediated cellular transformation and found that the HPV-16 E7 mutants Y25A, E26A, S31A, S32A, and E35A, but not L28A and N29A, caused loss of transformation ability. Preliminary data suggest loss of IRF-9 interaction with E7 mutants correlated with transformation. Our work suggests E7-IRF-9 interaction is important for the transforming ability of HPV-16 E7 and that HPV-16 E7 may interact with other IRF proteins that have IAD domains.     

Dual loci of DNA bending in the bovine papillomavirus upstream regulatory region

Recombinant clones containing all or portions of the bovine papillomavirus (BPV) upstream regulatory region (URR) were constructed. When analyzed by polyacrylamide gel electrophoresis, the cloned URR sequences exhibited electrophoretic properties characteristic of DNA containing bend sites. Two distinct bend centers were identified, mapping to approximately 7477 and 7790 respectively on the BPV genome. No other loci of static DNA bending were detected in the URR region of the BPV genome.     

Transmission of human papillomavirus type 11 infection by desquamated cornified cells

While much is known about the human papillomavirus (HPV) productive cycle, the mechanisms of virion transmission from person to person are poorly understood. The keratinocyte is the target cell of HPV infection. As keratinocytes differentiate, nuclei are lost and the cornified cell envelope develops. Layers of these desquamated cornified cells (DCCs) are continuously shed from the stratum corneum. Release of HPV requires the cornified cell envelope, a normally very durable structure, to break apart, liberating the contents of the cell. In differentiated keratinocytes infected with HPV 11, the cornified cell envelope is abnormally thin and fragile. In this study, DCCs from HPV 11-infected genital epithelium were used to investigate the mechanisms of viral transmission. First, HPV 11-infected tissue was examined for the presence of virions by transmission electron microscopy. Virions were observed in the nuclei of differentiated keratinocytes. In addition, virions were detected in the cytoplasm of DCCs that had undergone nuclear dissolution. Rarely, virions were observed outside of cells. Next, infectivity of intact and ruptured DCCs was tested in an assay performed in the athymic mouse xenograft system. High-titer cesium chloride gradient-purified HPV 11 virions infected 100% of recovered xenografts. Using intact DCCs derived from HPV 11-infected tissue, 62.5% of recovered xenografts were infected. To test the effects of mechanical stress on infectivity, DCCs were ruptured by sonication and used in the infectivity assay. The infectivity rate increased to 90%. We conclude that DCCs serve as vehicles for efficient, concentrated delivery of virions in HPV 11 infection.     

Absence of human papillomavirus sequences in ovarian pathologies.

The role of human papillomaviruses (HPVs) in ovarian epithelium (either normal or neoplastic) remains controversial. We have investigated by PCR the presence of HPV DNA in fresh tissue from ovarian neoplasms and in primary cell cultures established from either normal, benign or malignant ovarian surface epithelia. None of the fresh samples and primary ovarian cultures contained HPV DNA sequences.     

Oncogenic potential diverge among human papillomavirus type 16 natural variants

We compared E6/E7 protein properties of three different HPV-16 variants: AA, E-P and E-350G. Primary human foreskin keratinocytes (PHFK) were transduced with HPV-16 E6 and E7 and evaluated for proliferation and ability to grow in soft agar. E-P infected keratinocytes presented the lowest efficiency in colony formation. AA and E-350G keratinocytes attained higher capacity for in vitro transformation. We observed similar degradation of TP53 among HPV-16 variants. Furthermore, we accessed the expression profile in early (p5) and late passage (p30) transduced cells of 84 genes commonly involved in carcinogenesis. Most differences could be attributed to HPV-16 E6/E7 expression. In particular, we detected different expression of ITGA2 and CHEK2 in keratinocytes infected with AA and AA/E-350G late passage cells, respectively, and higher expression of MAP2K1 in E-350G transduced keratinocytes. Our results indicate differences among HPV-16 variants that could explain, at least in part, differences in oncogenic potential attributed to these variants.     

荧光定量聚合酶链反应检测人乳头瘤病毒6/11型

目的 了解女性阴道炎患者人乳头瘤病毒6／11型（HPV6／11）的感染情况。方法 用荧光定量聚合酶链反应（FQ－PCR）技术检测129例门诊患者阴道分泌物中HPV6／11的病毒拷贝数。结果 共检出HPV6／11阳笥者47例,阳性率为36．43％;拷贝数在10^5以上者39例,占阳性者中的82．98％;40岁以上年龄组阳性率高且病毒复制量均在10^5以上。结论 中老年阴道炎患者就诊晚,感染重。FQ－PCR检测HPV敏感、快速、准确,特别是其定量特点对临床很有意义。     

Detection of human papillomavirus type 16 DNA sequences in archival cervical tissues by the polymerase chain reaction.

We have evaluated the polymerase chain reaction for the detection of viral DNA sequences in paraffin-embedded archival tissues. In 63 frozen cervical biopsy specimens that were taken from premalignant and invasive lesions, Southern blotting detected human papillomavirus (HPV) type 16 DNA in 28 (44%) of the samples. In the polymerase chain reaction analysis of the formalin-fixed, paraffin-embedded mirror biopsy specimens, 46 (73%) of the tissues were found to be positive for HPV type 16. In three Southern blotting-positive cases, the DNA of the paraffin-embedded sections was too scant or too degraded to allow the detection of HPV DNA by the polymerase chain reaction. In 21 Southern blotting-negative cases, HPV type 16 DNA could be demonstrated in the archival sections by the polymerase chain reaction technique--a sensitivity improvement of more than 80% over the standard method of HPV detection in tissues.     

A key DNA-protein interaction determines the function of the 5'URR enhancer in human papillomavirus type 11.

The 5' end of the upstream regulatory region (URR) of human papillomavirus type 11 (HPV-11) has enhancer function and binds cellular proteins. We have determined that one particular motif, a CCNGTNAC pair, is both necessary and sufficient for enhancer activity. This enhancement of expression can be competed in vivo by concatenated double-stranded oligonucleotides, indicating that protein-DNA binding is a requisite for enhancer activity. A 41-kDa protein, present in all epithelial cells assayed, binds to this enhancer motif. The 5'URR fragment functions as an enhancer both in primary keratinocytes from a variety of body sites and in fibroblasts. We conclude that tissue specificity is not a feature of this enhancer, and that the 41-kDa binding protein is ubiquitous. These data provide evidence that the 5'URR enhancer activity is dependent on only a few sequences and perhaps only one protein.     

Evaluation of temperature sensitivity of human papillomavirus type 11 by using the human xenograft severe combined immunodeficiency mouse model.

The temperature sensitivity of human papillomavirus type 11 was evaluated by using a human xenograft severe combined immunodeficiency mouse model. Incubation of the virus for 1 h at a temperature higher than 56 degrees C but lower than 72 degrees C was sufficient to inhibit the virally induced growth of infected human tissue. However, 100 degrees C was necessary to completely inactivate HPV type 11 genome expression.     

DNA dot-blot hybridization implicates human papillomavirus type 11-DNA in epithelioma cuniculatum

Epithelioma cuniculatum is a rare, low-grade squamous cell carcinoma, belonging to the group of verrucous carcinomas. Evidence is presented that suggests that human papilloma virus type-11 may be involved in the pathogenesis of epithelioma cuniculatum. HPV-DNA was detected by dot-blot hybridization with 32P-labelled probe DNA. Plasmids containing HPV-DNA were isolated by the benzoylated naphthoylated DEAE cellulose method (BND-method), an improved procedure for routine detection of HPV-DNA.     

人乳头瘤病毒11型L1/E7嵌合DNA疫苗的构建及其诱导的免疫效应

Objective To construct chimerical DNA vaccine plasmid of human papiUomavirus type 11 (HPV11) L1-E7, and to evaluate its immunogenicity. Methods Molecular cloning techniques were used to construct recombinant plasmid PeDNA3 L1-E7 as a DNA vaccine. BALB/c mice were vaccinated with DNA recombinants through muscle injection. IL-2 and γ-INF secreted by immunized spleens lymphocyte and HPV 11 LI or E7 specific antibodies were assayed by ELISA method. Spleens lymphocyte proliferation was measured by MTT assay. Results The chimerical DNA plasmid of pcDNA3 LI-E7 was constructed correctly. Specific anti-HPV11 E7 and L1 antibodies, specific lymphocyte proliferation and secretions of IL-2 and γ-INF were detected in vaccinated mice. Conclusion Specific immune response, including cellular immunity and humoral immunity, could been detected in mice vaccinated with chimerical DNA vaccine of pcDNA3 L1-E7.     

人乳头瘤病毒11型L1/E7嵌合DNA疫苗的构建及其诱导的免疫效应

Objective To construct chimerical DNA vaccine plasmid of human papiUomavirus type 11 (HPV11) L1-E7, and to evaluate its immunogenicity. Methods Molecular cloning techniques were used to construct recombinant plasmid PeDNA3 L1-E7 as a DNA vaccine. BALB/c mice were vaccinated with DNA recombinants through muscle injection. IL-2 and γ-INF secreted by immunized spleens lymphocyte and HPV 11 LI or E7 specific antibodies were assayed by ELISA method. Spleens lymphocyte proliferation was measured by MTT assay. Results The chimerical DNA plasmid of pcDNA3 LI-E7 was constructed correctly. Specific anti-HPV11 E7 and L1 antibodies, specific lymphocyte proliferation and secretions of IL-2 and γ-INF were detected in vaccinated mice. Conclusion Specific immune response, including cellular immunity and humoral immunity, could been detected in mice vaccinated with chimerical DNA vaccine of pcDNA3 L1-E7.