The papillomavirus life cycle is tied to the differentiation of the stratified squamous epithelium that this virus infects. The ability to study the papillomavirus life cycle is facilitated by organotypic culturing techniques that allow one to closely recapitulate this terminal differentiation process in the laboratory. Current techniques allow for the establishment of recombinant wild-type or mutant human papillomavirus (HPV) genomes in transfected early-passage human foreskin keratinocytes (HFKs). These cells can then be used in organotypic culture to investigate the role of individual viral genes in different aspects of the viral life cycle. When using early-passage HFKs, there is a need for the transfected HPV genome to extend the life span of the cells in order to have sufficient cell generations in which to carry out organotypic culturing. The recent isolation of a spontaneously immortalized HFK cell line that supports the complete HPV life cycle has further allowed investigators to study wild-type or mutant papillomaviral genomes that do not confer immortalization. In this chapter, we describe the methodologies that permit the study of the HPV life cycle in this HFK cell line.

R-Ras regulates integrin function, but its effects on integrin signaling pathways have not been well described. We demonstrate that activation of R-Ras promoted focal adhesion formation and altered localization of the ␣2␤1 integrin from cell-cell to cell-matrix adhesions in breast epithelial cells. Constitutively activated R-Ras(38V) dramatically enhanced focal adhesion kinase (FAK) and p130Cas phosphorylation upon collagen stimulation or clustering of the ␣2␤1 integrin, even in the absence of increased ligand binding. Signaling events downstream of R-Ras differed from integrins and K-Ras, since pharmacological inhibition of Src or disruption of actin inhibited integrin-mediated FAK and p130Cas phosphorylation, focal adhesion formation, and migration in control and K-Ras(12V)-expressing cells but had minimal effect in cells expressing R-Ras(38V). Therefore, signaling from R-Ras to FAK and p130Cas has a component that is Src independent and not through classic integrin signaling pathways and a component that is Src dependent. R-Ras effector domain mutants and pharmacological inhibition suggest a partial role for phosphatidylinositol 3-kinase (PI3K), but not Raf, in R-Ras signaling to FAK and p130Cas . However, PI3K cannot account for the Srcindependent pathway, since simultaneous inhibition of both PI3K and Src did not completely block effects of R-Ras on FAK phosphorylation. Our results suggest that R-Ras promotes focal adhesion formation by signaling to FAK and p130Cas through a novel mechanism that differs from but synergizes with the ␣2␤1 integrin.

Human papillomaviruses (HPVs), most commonly the HPV16 genotype, are the principle etiological determinant for cervical cancer, a common cancer worldwide resulting in over 200,000 deaths annually. The oncogenic properties of HPVs are attributable in part to the virally encoded protein E7, best known for its ability to bind to and induce the degradation of the retinoblastoma tumor suppressor, pRb, and related "pocket proteins" p107 and p130. Previously, we defined a role for E7 in the productive stage of the HPV16 life cycle, which takes place in stratified squamous epithelia. HPV perturbs the normal processes of cell growth and differentiation of stratified squamous epithelia. HPVs reprogram cells to support continued DNA synthesis and inhibit their differentiation in the suprabasal compartment of the epithelia, where cells normally have withdrawn from the cell cycle and initiated a well-defined pattern of terminal differentiation. These virus-induced perturbations, which contribute to the production of progeny HPVs, are dependent on E7. In this study, we define the mechanism of action by which E7 contributes to the productive stage of the HPV16 life cycle. We found that the ability of HPV16 to reprogram suprabasal cells to support DNA synthesis correlates with E7's ability to bind pocket proteins but not its ability to induce their degradation. In contrast, the ability of HPV16 to perturb differentiation correlated with both E7's binding to and degradation of pocket proteins. These data indicate that different hallmarks of the productive stage of the HPV16 life cycle rely upon different sets of requirements for E7.Human papillomaviruses (HPVs) are small DNA tumor viruses that infect stratified squamous epithelial cells. There are over 100 genotypes of HPV that are classified as cutaneous or mucosotropic, based on whether they primarily infect the skin or the anogenital tract/cavity, respectively. The mucosotropic HPVs are further subclassified as low or high risk, depending on their etiological association with human cancers. High-risk HPVs, such as HPV16, are accepted as the main causal factor for cervical cancer, a leading cause of death among women worldwide, and other less common anogenital cancers including cancers of the vagina, vulva, penis, and anus (50, 52). In addition, high-risk HPVs are associated with a subset of oral cancers (17, 52). One of the HPV genes implicated in HPVassociated cancer is E7 (23,26,34,44). E7 also plays a critical role in the viral life cycle by reprogramming cells within the suprabasal compartment of stratified squamous epithelia to support DNA synthesis, a prerequisite for viral DNA amplification and production of progeny virus (12). E7 is a multifunctional protein best known for its ability to bind and inactivate the retinoblastoma tumor suppressor, pRb, and related "pocket proteins" p107 and p130 (10,28,36,42). In this study, we examined the mechanism of action by which E7 contributes to the viral life cycle and, in particular, the importance of E7 interaction with pRb and...

Background Africa’s economic transformation relies on a radical transformation of its higher education institutions. The establishment of regional higher education Centres of Excellence (CoE) across Africa through a World Bank support aims to stimulate the needed transformation in education and research. However, excellence is a vague, and often indiscriminately used concept in academic circles. More importantly, the manner in which aspiring institutions can achieve academic excellence is described inadequately. The main objective of this paper is to describe the core processes of excellence as a prerequisite to establishing academic CoE in Africa. Methods The paper relies on our collaborative discussions and real-world insight into the pursuit of academic excellence, a narrative review using Pubmed search for a contextual understanding of CoEs in Africa supplemented by a Google search for definitions of CoEs in academic contexts. Results We identified three key, synergistic processes of excellence central to institutionalizing academic CoEs: participatory leadership, knowledge management, and inter-disciplinary collaboration. (1) Participatory leadership encourages innovations to originate from the different parts of the organization, and facilitates ownership as well as a culture of excellence. (2) Centers of Excellence are future-oriented in that they are constantly seeking to achieve best practices, informed by the most up-to-date and cutting-edge research and information available. As such, the process by which centres facilitate the flow of knowledge within and outside the organization, or knowledge management, is critical to their success. (3) Such centres also rely on expertise from different disciplines and ‘engaged’ scholarship. This multidisciplinarity leads to improved research productivity and enhances the production of problem-solving innovations. Conclusion Participatory leadership, knowledge management, and inter-disciplinary collaborations are prerequisites to establishing academic CoEs in Africa. Future studies need to extend our findings to understand the processes key to productivity, competitiveness, institutionalization, and sustainability of academic CoEs in Africa.

The cytopathic effect (CPE) seen with some subgroups of avian sarcoma and leukosis virus (ASLV) is associated with viral Env activation of the death-promoting activity of TVB (a tumor necrosis factor receptorrelated receptor that is most closely related to mammalian TNF-related apoptosis-inducing ligand [TRAIL] receptors) and with viral superinfection leading to unintegrated viral DNA (UVD) accumulation, which is presumed to activate a cellular DNA damage response. In this study, we employed cells that express signalingdeficient ASLV receptors to demonstrate that an ASLV CPE can be uncoupled from the death-promoting functions of the TVB receptor. However, these cell-killing events were associated with much higher levels of viral superinfection and DNA accumulation than those seen when the virus used signaling-competent TVB receptors. These findings suggest that a putative cellular DNA damage response that is activated by UVD accumulation might act in concert with the death-signaling pathways activated by Env-TVB interactions to trigger cell death. Such a model is consistent with the well-established synergy that exists between TRAILsignaling pathways and DNA damage responses which is currently being exploited in cancer therapy regimens.A number of retroviruses can cause a cytopathic effect (CPE) that is attributed, at least in part, to a function of the viral envelope glycoprotein (Env) (14,29,30,33). For many retroviruses, the CPE is also associated with massive levels of viral superinfection and/or viral DNA accumulation (13,17,27,36,37,40). Increased levels of viral DNA have been postulated to directly trigger a DNA damage response either before or after the formation of the gapped retroviral DNA integration intermediate in cells that are deficient in the nonhomologous DNA end-joining pathway (10,11,21). However, if viral DNA accumulation is important for stimulating cell death, then its role cannot be universal because human immunodeficiency virus type 1 can cause a CPE in the absence of viral DNA synthesis (5,20).We are studying avian sarcoma and leukosis viruses (ASLVs) to better understand how retroviruses can kill their target cells. Certain subgroups of ASLV are cytopathic (e.g., subgroups B, D, and F). Infection by the cytopathic viral subgroups can lead to the death of up to 30 to 40% of target cells in culture during the acute phase of infection (36, 37). This CPE is associated with viral superinfection and increased levels of viral DNA that are not seen during infection by noncytopathic subgroups of ASLV. The determinants of the ASLV-B surface (SU) Env subunit that are important for triggering the viral CPE are also the same as those required for receptor usage (14), leading to the suggestion that Env-receptor interactions might contribute to the viral CPE. This notion was strengthened when the TVB receptor for cytopathic viral subgroups B and D was identified as a tumor necrosis factor receptor (TNFR)-related death receptor that is most closely related to the mammalian DR4 (TRAIL-R1) and DR5 (TRAIL...