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To determine the role of neutralizing antibody generated by human papillomavirus (HPV) infections, baseline levels of serum neutralizing antibodies directed against HPV 16 and cervical HPV DNA were determined in 242 unvaccinated women with low-grade cervical abnormalities, who were then monitored by cytology and colposcopy every 4 months. In women infected with HPV 16 (n = 42), abnormal cytology persisted longer in those positive for HPV 16-specific neutralizing antibodies at baseline (median time to cytological regression: 23.8 vs. 7.2 months). Progression to cervical precancer (cervical intraepithelial neoplasia grade 3) within 5 years occurred only among women carrying HPV 16-specific neutralizing antibodies ( P = 0.03, log-rank test). In women infected with types other than HPV 16 (n = 200), detection of HPV 16-specific neutralizing antibodies was not correlated with disease outcome. In conclusion, development of specific neutralizing antibodies following natural HPV 16 infection did not favor a better outcome of low-grade cervical lesions induced by HPV 16 or by other types; rather, detection of neutralizing antibodies generated by current infection may reflect viral persistence and thus help identify those who are at high risk of disease progression. J. Med. Virol. 84: 1128-1134, 2012. © 2012 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Expression of a therapeutic gene in the skeletal muscle is a practical strategy to compensate a patients' insufficient circulating factor. Its clinical application requires a muscle-targeting vector capable of inducing a continuous high-level transgene expression. We modified an adeno-associated virus serotype 2 (AAV2) vector expressing luciferase from the mouse muscle creatine kinase gene promoter-enhancer (Ckm). First, AAVS1 insulator was inserted into the vector genome for transcriptional enhancement. This increased transduction of mouse quadriceps muscle by 11-fold at 4 weeks after intramuscular injection. Second, two capsid modifications were combined (21F capsid): incorporation of a segment of AAV1 capsid to produce a hybrid capsid and substitution of a tyrosine with a phenylalanine. Use of 21F capsid increased muscle transduction further by 18-fold, resulting in 200-fold higher efficacy than that of the unmodified vector. Compared with a vector having human elongation factor 1α promoter which showed similar efficacy in the muscle, this vector having Ckm transduced non-muscle organs less efficiently after intravenous administration. The AAV2 vector composed of the modified genome and capsid provides a backbone to develop a clinical vector expressing a therapeutic gene in the muscle. [ABSTRACT FROM AUTHOR]

Genotyping human papillomavirus (HPV) in clinical specimens is important because each HPV type has different oncogenic potential. Amplification of HPV DNA by PCR with the consensus primers that are derived from the consensus sequences of the L1 gene has been used widely for the genotyping. As recent studies have shown that the cervical specimens often contain HPV of multiple types, it is necessary to confirm whether the PCR with the consensus primers amplifies multiple types of HPV DNA without bias. We amplified HPV DNA in the test samples by PCR with three commonly used consensus primer pairs (L1C1/L1C2+C2M, MY09/11, and GP5+/6+), and the resultant amplicons were identified by hybridization with type-specific probes on a nylon membrane. L1C1/L1C2+C2M showed a higher sensitivity than the other primers, as defined by the ability to detect HPV DNA, on test samples containing serially diluted one of HPV16, 18, 51, 52, and 58 plasmids. L1C1/L1C2+C2M failed to amplify HPV16 in the mixed test samples containing HPV16, and either 18 or 51. The three consensus primers frequently caused incorrect genotyping in the selected clinical specimens containing HPV16 and one or two of HPV18, 31, 51, 52, and 58. The data indicate that PCR with consensus primers is not suitable for genotyping HPV in specimens containing multiple HPV types, and suggest that the genotyping data obtained by such a method should be carefully interpreted. ( Cancer Sci 2011; 102: 1223-1227) [ABSTRACT FROM AUTHOR]

Human immunodeficiency virus type 1 protease (HIV-1 PR) cleaves two viral precursor proteins, Gag and Gag-Pol, at multiple sites. Although the processing proceeds in the rank order to assure effective viral replication, the molecular mechanisms by which the order is regulated are not fully understood. In this study, we used bioinformatics approaches to examine whether the folding preferences of the cleavage junctions influence their cleavabilities by HIV-1 PR. The folding of the eight-amino-acid peptides corresponding to the seven cleavage junctions of the HIV-1 Gag and Gag-Pol precursors were simulated in the PR-free and PR-bound states with molecular dynamics and homology modeling methods, and the relationships between the folding parameters and the reported kinetic parameters of the HIV-1 peptides were analyzed. We found that a folding preference for forming a dihedral angle of Cβ (P1)-Cα (P1)- Cα (P1')-Cβ (P1') in the range of 150 to 180 degrees in the PR-free state was positively correlated with the 1/K (R = 0.95, P = 0.0008) and that the dihedral angle of the O (P2)-C (P2)- C (P1)- O (P1) of the main chains in the PR-bound state was negatively correlated with k (R = 0.94, P = 0.001). We further found that these two folding properties influenced the overall cleavability of the precursor protein when the sizes of the side chains at the P1 site were similar. These data suggest that the dihedral angles at the specific positions around the cleavage junctions before and after binding to PR are both critical for regulating the cleavability of precursor proteins by HIV-1 PR. [ABSTRACT FROM AUTHOR]

Replication of human papillomavirus (HPV) genomes requires an origin of replication and two viral proteins: the DNA helicase E1 and the auxiliary factor E2. To dissect the profile of HPV replication in the epithelium, we analyzed replication of an HPV16 origin-containing plasmid in human epithelial cell extracts supplemented with purified E1 and E2. We found that in addition to well-defined circular replication products, high-molecular-weight DNA was synthesized in a manner that depended on the origin, E1 and E2. The high-molecular-weight DNA was converted to a unit-length linear DNA by treatment with restriction enzymes that cleave the plasmid once, implying that a concatemeric DNA was generated by rolling circle replication. Nicking or relaxing the template plasmid enhanced the level of HPV rolling circle replication. In contrast, the addition of an extract from non-epithelial cells diminished the generation of the rolling circle replication product in the epithelial cell extract, indicating factors that counteract HPV rolling circle replication. These results suggest a rolling circle replication mechanism for the HPV genome in cervical epithelial cells, which may have physiological implications for generation of the tandem-repeated HPV genomes occasionally found integrated into the chromosome of cervical cancer cells. [ABSTRACT FROM AUTHOR]

Background Efficient and continuous expression of a therapeutic transgene is a key factor for improving the efficacy of gene therapy. Some insulators are known to contribute to continuous high-level expression of a therapeutic transgene. Methods Using the human AAVS1 insulator (DHS) found in the AAVS1 DNase I hypersensitive site, chicken β-globin insulator (cHS4) and sea urchin arylsufatase insulator (Ars), we newly constructed three recombinant adeno-associated virus vectors (rAAV) and examined their capability of transducing the mouse quadriceps muscle. Results DHS increased transgene expression from the human elongation factor 1α promoter (EF) by 1000-fold, up to the high level achieved by the human cytomegalovirus immediate early promoter/enhancer (CMV), which comprises an extremely strong promoter for driving a transgene. cHS4 enhanced the expression by 100-fold, whereas Ars did not. The enhanced expression was maintained for at least 24 weeks. Vector copy numbers were similar with and without DHS or cHS4; thus, the enhancement is most likely due to up-regulated transcription. Neither DHS, nor cHS4 affected transgene expression from CMV. DHS enhanced expression from the human muscle creatine kinase promoter/enhancer by 100-fold in mice, as did DHS from EF. Conclusions Although DHS was unable to further enhance high expression from the strong viral enhancer/promoter, it enhanced low expression from the human promoters by 100- to 1000-fold. Thus, DHS may be useful for constructing rAAVs that express a therapeutic transgene from less efficient, tissue specific promoters. Copyright © 2009 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The third variable region (V3) of the human immunodeficiency virus type 1 (HIV-1) envelope gp120 subunit participates in determination of viral infection coreceptor tropism and host humoral immune responses. Positive charge of the V3 plays a key role in determining viral coreceptor tropism. Here, we examined by bioinformatics, experimental, and protein modelling approaches whether the net positive charge of V3 sequence regulates viral sensitivity to humoral immunity. We chose HIV-1 CRF01şAE strain as a model virus to address the question. Diversity analyses using CRF01şAE V3 sequences from 37 countries during 1984 and 2005 (n = 1361) revealed that reduction in the V3's net positive charge makes V3 less variable due to limited positive selection. Consistently, neutralization assay using CRF01şAE V3 recombinant viruses (n = 30) showed that the reduction in the V3's net positive charge rendered HIV-1 less sensitive to neutralization by the blood anti-V3 antibodies. The especially neutralization resistant V3 sequences were the particular subset of the CCR5-tropic V3 sequences with net positive charges of +2 to +4. Molecular dynamics simulation of the gp120 monomers showed that the V3's net positive charge regulates the V3 configuration. This and reported gp120 structural data predict a less-exposed V3 with a reduced net positive charge in the native gp120 trimer context. Taken together, these data suggest a key role of the V3's net positive charge in the immunological escape and coreceptor tropism evolution of HIV-1 CRF01şAE in vivo. The findings have molecular implications for the adaptive evolution and vaccine design of HIV-1. [ABSTRACT FROM AUTHOR]

Human papillomavirus type 16 (HPV16) DNA replication, which requires two viral proteins E1 and E2, occurs only in the differentiating epithelium. Besides the general factors necessary for cellular DNA synthesis, other unidentified cellular factors are assumed to be involved in the regulation of HPV DNA replication. In the present study, we found that the POU-domain transcription factor human Skn-1a, which induces the terminal differentiation of keratinocytes and activates the HPV16 late promoter, enhanced the transient replication of a plasmid containing the HPV16 replication origin in HEK293 cells when co-transfected with a plasmid expressing E1 and E2. An electrophoretic mobility shift assay with a bacterially expressed human Skn-1a or an extract of HeLa cells over-expressing human Skn-1a revealed the presence of two human Skn-1a binding sites that are distinct from the known three sites, near the replication origin. A chromatin immunoprecipitation analysis showed that human Skn-1a bound to these sites in cells. Nucleotide substitutions in the sites abolished the binding of human Skn-1a and the human Skn-1a-mediated replication enhancement. The data strongly suggest that, through the binding to the two sites, human Skn-1a enhances HPV DNA replication. [ABSTRACT FROM AUTHOR]

Infection with human papillomavirus 16 (HPV16), which is one of the 15 types of HPV causally associated with cervical cancer and accounts for 50% of the cases, can be prevented in a type-specific manner by an HPV16 virus-like particle (VLP) vaccine comprised of particles of the L1 protein alone. We attempted to modify the VLP vaccine by inserting the HPV16 L2-peptides including cross-neutralization epitopes into the L1 polypeptide. The chimeric L1 had, between L1 amino acids (aa) 430 and 433, the L2 sequence of aa 18-38, 56-75, or 96-115 (with the replacements of S at aa 101 and T at aa 112 with L and S, respectively). The three chimeric L1s were each expressed from the recombinant baculovirus in insect Sf9 cells, and the resultant VLPs were characterized. The chimeric VLPs were shown to present the L2-peptides on their surface. By immunizing rabbits with the VLPs, it was shown that they retained capability to induce the antibody neutralizing HPV16 and acquired capability to elicit antibodies cross-neutralizing the infectious HPV18, 31, 52, and 58 pseudovirions. Although the cross-neutralizing titers were lower than the type-specific neutralizing titer, the results suggest that the chimeric VLPs have potential to serve as a vaccine candidate for a broad spectrum of high-risk HPVs. J. Med. Virol. 80:841-846, 2008. © 2008 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

Recently, we have identified human scribble (hScrib), human homolog of the Drosophila tumor suppressor Scribble, as a substrate of human papillomavirus E6 oncoproteins for ubiquitin-mediated degradation dependent on ubiquitin-protein ligase E6AP. Human Scribble, classified as a LAP protein containing eucine-rich repeats nd DZ domains, interacts with E6 through its PDZ domains and C-terminal PDZ domain-binding motif of E6 protein. Interaction between human Discs Large (hDlg), which is a substrate of E6 for the ubiquitin-mediated degradation, and adenomatous polyposis coli (APC) has been shown. Here, we investigated whether hScrib and APC interact with each other in vitro and in vivo. Interaction between hScrib and APC is mediated by the PDZ domains 1 and 4 of hScrib and C-terminal PDZ domain-binding motif of APC. Human Scribble co-localized with APC at the synaptic sites of hippocampal neuron and at the tip of membrane protrusion in the epithelial cell line. Interference of the interaction between hScrib and APC caused disruption of adherens junction. Knockdown of hScrib expression by RNAi disrupts localization of APC at the adherens junction. These data suggest that hScrib may participate in the hDlg-APC complex through its PDZ domains and regulate cell cycle and neural function by associating with APC. [ABSTRACT FROM AUTHOR]

The POU transcription factor human Skn-1a (hSkn-1a) specifically promotes the proliferation of keratinocytes and enhances their differentiation. We examined the effects of hSkn-1a on cervical cancer cell lines of epithelial origin, in which the differentiation program is interrupted. From HeLa/Tet-On, a clone that can be induced to make hSkn-1a by doxycycline (HeLa/hSkn-1a) was prepared and characterized. Shortly after the induction, the cells expressed cytokeratin 10 (K10), a major marker protein in differentiating keratinocytes. While maintained for several days in the presence of doxycycline, the HeLa/hSkn-1a cells showed a slightly prolonged time of population doubling, the occasional appearance of flat cells with lowered DNA synthesis, and a low level of apoptotic DNA fragmentation. In SiHa and HeLa S3 cultures, K10 mRNA and apoptotic DNA fragmentation were detected at 48?h after infection with an adenoviral vector capable of expressing hSkn-1a. A colony inhibition assay showed that the growth of HeLa S3, SiHa, CaSki, and C-33A cells was repressed, as seen from the decreased number and average size of the drug-resistant colonies at 2 or 3 weeks after transfection with a plasmid that can express hSkn-1a and neomycin resistance gene. These results suggest that the expression of hSkn-1a represses the growth of the cervical cancer cells through the partial resumption of the differentiation pathway followed by slow suppression of cell replication and apoptosis.Oncogene (2004) 23, 5014-5022. doi:10.1038/sj.onc.1207653 Published online 12 April 2004 [ABSTRACT FROM AUTHOR]

Examines the essential protein required to trigger initiation of DNA replication in G1 phase. Comparison of cDNA and the genomic sequence; Difference of splicing in HeLa cells; Details on the binding site of CDC45 protein in vitro to human minichromosome maintenance protein.