Pathogenesis of SIV encephalitis. Selection and replication of neurovirulent SIV.

To investigate the viral and host factors that contribute to neurological disease, nine macaques were intravenously co-inoculated with SIV/DeltaB670, a primary isolate of SIV consisting of at least 21 different genotypes, and SIV/17E-Fr, a neurovirulent recombinant clone. CD4+ cell counts and antigenemia were measured throughout infection. The SIV env V1 region was amplified from brain and peripheral blood mononuclear cell DNA to compare the genotypes present in brain and blood. Seven of the 9 macaques (78%) developed typical SIV-associated neurological lesions classified as severe (4 macaques), moderate (2 macaques), or mild (1 macaque) with a mean time to euthanasia of 7 months. Macaques with severe neurological lesions progressed more rapidly, with a mean time to euthanasia of 3-6 months. SIV/17E-Fr was detected in brain homogenates from all four macaques with severe encephalitis, and in three of the four, SIV/17E-Fr was the only genotype identified in the central nervous system. Macaques with less severe or no neurological lesions usually had one of various genotypes of SIV/DeltaB670 in brain. A variety of genotypes of SIV/DeltaB670 and SIV/17E-Fr were detected in peripheral blood mononuclear cells throughout infection. Macaques with severe neurological lesions had the most precipitous declines in CD4+ cell counts, the highest levels of antigenemia, and the greatest expression of viral RNA and protein in the central nervous system. Macaca nemestrina were more likely to develop severe neurological lesions than M. mulatta or M. fascicularis (P = 0.048). This study demonstrated that neurovirulent strains within the virus swarm can selectively enter and become established in the central nervous system and that the neurological lesions that develop are correlated with the development of host immunosuppression. The species differences in severity of neurological lesions seen in this study suggest that host factors are also important in determining the outcome of lentiviral infection.     

E2F1促进内源性XRCC1启动子的表达

目的 探讨E2F1对XRCC1的调节作用及其意义.方法 将受四环素调节的启动子控制的E2F1表达载体(tet-E2F1)和突变的E2F1(tet-132E)表达载体分别转染至Saos2细胞,构建XRCC1启动子荧光报告载体,同时转染特异的XRCC1启动子荧光报告载体和不同数量的E2F1表达载体以及E2F2、E2F4、E2F4表达载体进入Saos2细胞,收集细胞,进行荧光素酶分析,570 nm波长读取吸光度值.结果 转染E2F1表达载体和XRCC1启动子荧光报告载体,提高E2F1载体的数量可以增加荧光素酶的活性,相反.突变的E2F1(132E)不能激活XRCC1启动子荧光报告基因.结论 E2F1能够激活XRCC1启动子,并且能够使XRCC1启动子表达增强.     

Herpes simplex virus induces intracellular redistribution of E2F4 and accumulation of E2F pocket protein complexes.

Accumulation of E2F-p107 and E2F-pRB DNA binding complexes occurred after herpes simplex virus infection of U2-OS cells. Accumulation of E2F-p107 also occurred by 4 h p.i. in C33 cells. This corresponded to a time when host DNA synthesis was reduced by 50%, and lagged by >/=1 h, the onset of viral DNA synthesis. To determine the basis for increased nuclear E2F complexes, we investigated the effects of virus infection on the intracellular distribution of the E2F-dependent DNA binding complexes and their protein constituents. Western blot analyses of whole cell extracts revealed that amounts of E2F4, E2F1, DP1, and p107 remained unchanged after infection of C33 cells. Analysis of cytoplasmic and nuclear fractions, however, revealed that cytoplasmic E2F4 decreased and nuclear E2F4 increased. This correlated with a loss of cytoplasmic E2F DNA-binding activity and a corresponding increase in nuclear DNA-binding activity. Concomitant with its redistribution, the apparent molecular weight of total and p107-associated E2F4 increased, at least partially as a result of protein phosphorylation. Increased nuclear E2F-pRB in U2-OS cells was accompanied by the conversion of pRB from a hyper- to a hypophosphorylated state. Infection of U2-OS cells with viral mutants indicated that viral protein IE ICP4 was necessary for the decrease in cytoplasmic E2F-p107, and that viral protein DE ICP8 was required for nuclear accumulation of p107-E2F. In contrast, ICP8 was not required for accumulation of E2F-pRB. These results indicate that the increase in E2F-p107 may be explained by the redistribution and modification of E2F4 and the increase in E2F-pRB by modification of pRB.     

TRAF4通过泛素化E2F1调控乳腺癌细胞凋亡

目的 探讨肿瘤坏死因子受体相关因子4(TRAF4)是否通过E2F1转录因子(E2F1)调控乳腺癌细胞凋亡.方法 流式细胞分析检测TRAF4对乳腺癌细胞凋亡的调控情况以及E2Fl在其中的作用;Western blot检测TRAF4、精氨酸甲基转移酶5(PRMT5)和E2F1之间的调控关系;免疫荧光及免疫共沉淀检测TRAF...     

Protein expression profiles and prognostic value of E2F family members in clear cell renal cell carcinoma

The derangement of the cell cycle facilitates uncontrolled cell proliferation and acquisition of genetic alterations favorable for malignancy. However, the protein expression profiles of E2 F family cell cycle regulators in clear cell renal cell carcinoma (ccRCC) have not yet been thoroughly investigated. In this study, we aimed to examine the protein expression profiles and prognostic value of E2 F1, E2 F3, and E2 F4 in ccRCC cases. The immunohistochemical expression of E2 F1, E2 F3, and E2 F4 was quantitatively scored in 180 ccRCC tumor tissues and 79 normal kidney tissues. The prognostic implications of these E2 F members were determined. We found that ccRCC tumor cells showed higher nuclear expression of E2 F1, E2 F3 and E2 F4 than normal kidney samples. High E2 F1 and E2 F3 expression in tumor cells was associated with poor prognostic factors of ccRCC, whereas high E2 F4 correlated with beneficial prognostic factors. High expression of E2 F1 and E2 F3 in tumor cells was correlated with a poor overall and recurrence-free survival, while high E2 F4 expression did not. In conclusion, E2 F1, E2 F3 and E2 F4 may function as oncogenes during tumorigenesis of ccRCC, although they contribute to the progression of ccRCC in different ways. Additional studies are required to clarify the conflicting role of E2 F4 in the tumor evolution of ccRCC.     

HIV-2 and SIV Vector Systems

Lentiviral vectors have received much attention in recent years due to their ability to efficiently transduce non-dividing cells. Of the lentiviruses HIV-2 and SIV offer several unique benefits as the basis for lentiviral vector design. HIV-1, HIV-2 and SIV remain the only known primate lentiviruses, and consequently are among the most extensively studied viruses known. Substantial effort has been devoted towards identifying the pathogenic determinants of the primate lentiviruses and towards understanding their replication within primates. Of the primate lentiviruses, the pathogenicity and rates of transmission of HIV-2 and SIV fall far below that of HIV-1, potentially providing vectors based upon HIV-2/SIV with a greater degree of biosafety. Last, and perhaps most importantly, HIV-2 and SIV are viruses which may be studied within non-human primate models susceptible to AIDS-like disease, making vectors based upon these viruses accessible to substantial preclinical evaluation. We approach this Chapter presenting information regarding the basic biology of HIV-2 and SIV and conclude by pointing to how unique features of HIV-2 and SIV are well suited to vector design, hoping to leave the reader with a greater appreciation of the potential these viruses offer within the field of gene transfer applications.     

Immunoglobulin E in patients with Japanese encephalitis.

Significantly high levels of immunoglobulin E in the acute sera of encephalitis cases (suspected or confirmed as Japanese encephalitis) declined sharply during early convalescence.     

T cell receptor recognition motifs govern immune escape patterns in acute SIV infection

Escape from adaptive T cell immunity through transmutation of viral antigenic structure is a cardinal feature in the pathogenesis of SIV/HIV infection and a major obstacle to antiretroviral vaccine development. However, the molecular determinants of this phenomenon at the T cell receptor (TCR)-antigen interface are unknown. Here, we show that mutational escape is intimately linked to the structural configuration of constituent TCR clonotypes within virus-specific CD8(+) T cell populations. Analysis of 3416 SIV-specific TCR sequences revealed that polyclonal T cell populations characterized by highly conserved TCRB CDR3 motifs were rendered ineffectual by single residue mutations in the cognate viral epitope. Conversely, diverse clonotypic repertoires without discernible motifs were not associated with viral escape. Thus, fundamental differences in the mode of antigen engagement direct the pattern of adaptive viral evolution. These findings have profound implications for the development of vaccines that elicit T cell immunity to combat pathogens with unstable genomes.     

卵巢癌中E2F1通过影响miR-106b-5P调节RhoC的表达

目的探讨卵巢癌中E2F1、miR-106b-5P以及RhoC三者的表达的关系。方法使用Spearman相关分析方法分析卵巢癌组织中E2F1和miR-106b-5P表达水平的相关关系;OVCAR3和A2780细胞中转染或沉默E2F1,通过RT-PCR检测miR-106b-5P和RhoC的表达,转染miR-106b-5P后检测RhoC的表达。结果经分析发现卵巢癌组织中E2F1和miR-106b-5P表达水平呈负相关。卵巢癌细胞转染E2F1后miR-106b-5P表达水平下降,RhoC的表达水平上升;转染si-E2F1后结果相反;而在卵巢癌细胞中转染miR-106b-5P后发现RhoC的表达水平下降。结论 E2F1负调控miR-106b-5P表达调控RhoC的表达。