关于人乳头状瘤病毒16型启动子控制区域switch位点 …

目的 细胞转录调节因子ＹＹ１对人乳头状瘤病毒１６型（Ｈｕｍａｎ ｐａｐｉｌｌｏｍａｖｉｒｕｓ ｔｙｐｅ１６ ＨＰＶ１６）早期启动子Ｐ９７起抑制作用,而对ＨＰＶ１８早期启动子Ｐ１０５的调节作用受位于ＹＹ１特异性结合位点上游序列的ｓｗｉｔｃｈ位点的影响。本研究观测在ＨＰＶ１６调节区域有无类似的ｓｗｉｔｃｈ位点存在。     

Human papillomavirus 16 variants from Zambian women with normal pap smears

Human papillomavirus (HPV) type 16 is the most prevalent high-risk viral genotype associated with cervical cancer. Six distinct phylogenetic clusters of HPVs have been identified and are distributed differently across five continents. HPV16 DNA was extracted from cervicolavage samples from women with normal pap smears. The LCR regions were amplified in triplicate, cloned, sequenced, and analyzed from a total of 11 recovered HPV16 positive samples [Ng'andwe et al. (2007): BMC Infect Dis 7:77] were analyzed for sequence variation. The HPV16 LCR variants were assessed for promoter activity by use of a luciferase reporter gene. Six novel HPV16 variants with nucleotide exchanges in the LCR region were identified. Five clones were classified as European group HPV16 variants and one as an African group variant. Two of these variants had relatively lower promoter activity, 30% of that of the wild-type strain. The decreased promoter activity of some HPV16 variants may decrease expression of viral oncogenes and may be linked with the development, phenotype and severity of the cervical lesions in women infected with these across HPV16 variants.     

The prevalence of HPV-18 and variants of E6 gene isolated from cervical cancer patients in Taiwan.

BACKGROUND: Cervical cancer is the second most common cancer in women worldwide. It has been considered that human papillomavirus (HPV) is associated with cervical cancer. Currently, more than 80 different serotypes of HPV have been characterized and they are divided into low- and high-risk groups. The most common types that lead to cervical cancer are HPV-16 and -18. The viral oncogenes E6 and E7 are associated with the development of cervical cancer. In previous study, the variants of HPV-16 E6 gene have been reported. It suggests that variants may influence the morbidity of carcinogenesis, but the variant study on HPV-18 remains unknown. OBJECTIVES: To identify the variants of integrated HPV-18 E6 gene in the prevalent infection of HPV-18 of cervical cancer patients. STUDY DESIGN: 25 cervical cancer patients were clinically identified and the biopsies were obtained. The infectious HPV types were identified by PCR and Southern blotting analysis. The DNA fragments of the integrated HPV-18 E6 were amplified by PCR and cloned. The nucleotide sequences were obtained by sequencing. RESULTS: The prevalence of HPV infection in our 25 cases was HPV-18 (100%) and 7 out of these 25 cases (28%) were co-infected with HPV-16. The most dominant mutation among 25 tested patients was a silence mutation C183G of the E6 coding region. CONCLUSIONS: The prevalent HPV infectious serotype is HPV-18, which differs from the worldwide prevalent type. The identified HPV-18 E6 variants had a unique silence mutation located on C183G in E6 coding region.     

Polymorphism of human papillomavirus type 31 isolates infecting the genital tract of HIV-seropositive and HIV-seronegative women at risk for HIV infection

The genomic polymorphism of high-risk human papillomavirus (HPV) for types other than 16 has not been extensively described. We describe here the genomic polymorphism of high-risk HPV type 31 in 79 women (62 HIV-seropositive, 17 HIV-seronegative) by PCR-sequencing of the long control region (LCR), E6 and E7. LCR polymorphism was generated by 25 (6.4%) single-nucleotide variations over 391 bases. Each variant compared to the prototype contained from 2 to 13 variations (mean of 9.4 +/- 3.3, median of 10). Considering the number of variation sites in each region of HPV genome, the LCR was more variable than E6 (13 over 496 nucleotide (nt), P=0.03) and E7 (9 over 296 nt, P=0.03). Non-synonymous nucleotide variations were found in 31 (75.6%) of 41 isolates and were observed at six positions in E6. Each of the 8 HPV-31 E7 variants contained from 2 to 5 mutations (mean of 4.29 +/- 1.11, median of 5) compared to the prototype. Three non-synonymous E6 and E7 variations were within cysteine arrays. The LCR prototype was significantly over-represented in Caucasian women (14 (25%) of 56) compared to women of African descent (0 (0%) of 15 women, P=0.03). Four (23.5%) of 17 women with persistent versus 6 (25.0%) of 24 women with transient infections were infected by the prototype (P=1.00). HPV-31 LCR was more polymorphic than oncogenes and was associated with ethnicity.     

E6 and E7 oncoproteins from human papillomavirus type 16 induce activation of human transforming growth factor beta1 promoter throughout Sp1 recognition sequence

Human Papillomavirus (HPV) infection is the main etiologic agent of cervical cancer and HPV E6 and E7 oncogenes trans-regulate many cellular genes. An association between TGF-beta1 gene expression and cervical cancer development has been suggested; however, the mechanisms by which HPV influences TGF-beta1 expression remain unclear. In the present study we analyzed the mechanism through which HPV-16 E6 and E7 oncoproteins regulate the TGF-beta1 promoter in cervical tumor cells. Our results showed that E6 and E7 increased TGF-beta1 promoter activity. Furthermore, we identified a specific DNA sequence motif in the TGF-beta1 core promoter that is responsible for trans-activation and that corresponds to the Sp1e-binding site associated with HPV-16 E6 and E7 oncoproteins. Mutational analysis showed that the Sp1e recognition site abolished the trans-activation caused by E6 and E7. These results suggest a physical interaction and functional cooperation between viral oncoproteins and cellular regulatory elements of the TGF-beta1 promoter, and may explain the contribution of HPV-16 to TGF-beta1 gene expression in cervical cancer.     

Primary human cervical carcinoma cells require human papillomavirus E6 and E7 expression for ongoing proliferation

Repression of human papillomavirus (HPV) E6 and E7 oncogenes in established cervical carcinoma cell lines causes senescence due to reactivation of cellular tumor suppressor pathways. Here, we determined whether ongoing expression of HPV16 or HPV18 oncogenes is required for the proliferation of primary human cervical carcinoma cells in serum-free conditions at low passage number after isolation from patients. We used an SV40 viral vector expressing the bovine papillomavirus E2 protein to repress E6 and E7 in these cells. To enable efficient SV40 infection and E2 gene delivery, we first incubated the primary cervical cancer cells with the ganglioside GM1, a cell-surface receptor for SV40 that is limiting in these cells. Repression of HPV in primary cervical carcinoma cells caused them to undergo senescence, but the E2 protein had little effect on HPV-negative primary cells. These data suggest that E6 and E7 dependence is an inherent property of human cervical cancer cells.     

细胞转录调节因子YY1及其对人乳头瘤病毒16型早期？…

目的 为了检测ＹＹ１在不同宫颈癌细胞及人乳头瘤病毒易感细胞中的表达、功能状态和ＹＹ１位点破坏所诱导的Ｐ９７活性增强效应。方法 提取了４种宫颈癌细胞和２种人角源细胞胞核蛋白，检测其内源性ＹＹ１蛋白。同时将带有ＨＰＶ１６标准ＬＣＲ和ＹＹ１位点突变ＬＣＲ序列的荧光素酶质粒短暂转染上述细胞以检测Ｐ９７活性。结果 所有被检测细胞均含有良好生物学活性的ＹＹ１蛋白，其蛋白量在各细胞间无明显差别。ＨＰＶ１６ＬＣＲ     

细胞转录调节因子YY1及其对人乳头瘤病毒16型早期启动子P97抑制效应广泛存在于人上皮细胞

目的为了检测ＹＹ１在不同宫颈癌细胞及人乳头瘤病毒易感细胞中的表达、功能状态和ＹＹ１位点破坏所诱导的Ｐ９７活性增强效应。方法提取了４种宫颈癌细胞和２种人角源细胞胞核蛋白，检测其内源性ＹＹ１蛋白。同时将带有ＨＰＶ１６标准ＬＣＲ和ＹＹ１位点突变ＬＣＲ序列的荧光素酶质粒短暂转染上述细胞以检测Ｐ９７活性。结果所有被检细胞均含有良好生物学活性的ＹＹ１蛋白，其蛋白含量在各细胞系间无明显差别。ＨＰＶ１６ＬＣＲ上ＹＹ１位点的破坏可在多种细胞，包括人类原代角源细胞中诱导Ｐ９７活性增强。结论表明ＹＹ１蛋白调节系统广泛存于ＨＰＶ易感细胞系内。同时我们还发现转录激活因子ＮＦ１在Ｃ３３ａ细胞中的含量明显高于ＨＴ３细胞，并影响ＹＹ１位点改变所致的Ｐ９７活性增强效应。这提示在不同的细胞系中活性蛋白的表达和含量可能不同     

98例宫颈癌人乳头状瘤病毒16型E6基因突变及多态性分析

目的 研究湖北地区宫颈癌患者人乳头状瘤病毒16型(HPV16)E6基因点突变分布及频率,与国内外其他研究人员发现的E6突变进行对比,分析E6突变在宫颈癌发生中的意义.方法 从宫颈癌患者手术切除标本中提取组织DNA,用HPV16 E6特异性引物进行PCR扩增,对扩增的E6基因片段进行测序分析.结果 在35例宫颈癌组织DNA中有18例发生E6基因178位核苷酸的突变,变突频率为51.43%,相应核苷酸改变为Asp→Glu,442位核苷酸有4例发生核苷酸序列的改变,突变频率为11.43%,另有10例发生1～2个核苷酸序列的改变.结论 湖北地区98例宫颈癌患者人乳头状瘤病毒E6基因存在高频率的178和442位核苷酸突变,一些为新发现的核苷酸序列的突变,这些突变在宫颈癌发生中的作用有待于进一步研究.