E2F modulates keratinocyte squamous differentiation. Implications for E2F inhibition in squamous cell carcinoma

E2F regulation is essential for normal cell cycle progression. Therefore, it is not surprising that squamous cell carcinoma cell lines (SCC) overexpress E2F1 and exhibit deregulated E2F activity when compared with normal keratinocytes. Indeed, deliberate E2F1 deregulation has been shown to induce hyperplasia and skin tumor formation. In this study, we report on a dual role for E2F as a mediator of keratinocyte proliferation and modulator of squamous differentiation. Overexpression of E2F isoforms in confluent primary keratinocyte cultures resulted in suppression of differentiation-associated markers. Moreover, we found that the DNA binding domain and the trans-activation domain of E2F1 are important in mediating suppression of differentiation. Use of a dominant/negative form of E2F1 ( E2F d/n) found that E2F inhibition alone is sufficient to suppress the activity of proliferation-associated markers but is not capable of inducing differentiation markers. However, if the E2F d/n is expressed in differentiated keratinocytes, differentiation marker activity is further induced, suggesting that E2F may act as a modulator of squamous differentiation. We therefore examined the effects of E2F d/n in a differentiation- insensitive SCC cell line. We found that treatment with the differentiating agent, 12-O-tetradecanoyl- phorbol-13-acetate (TPA), or expression of E2F d/n alone had no effect on differentiation markers. However, a combination of E2F d/n + TPA induced the expression of differentiation markers. Combined, these data indicate that E2F may play a key role in keratinocyte differentiation. These data also illustrate the unique potential of anti-E2F therapies in arresting proliferation and inducing differentiation of SCCs.

Identification and in vivo characterization of PpaA, a regulator of photosystem formation in Rhodobacter sphaeroides

A regulatory protein, PpaA, involved in photosystem formation in the anoxygenic phototrophic proteobacterium Rhodobacter sphaeroides has been identified and characterized in vivo. Based on the phenotypes of cells expressing the ppaA gene in extra copy and on the phenotype of the ppaA null mutant, it was concluded that PpaA activates photopigment production and puc operon expression under aerobic conditions. This is in contrast to the function of the PpaA homologue from Rhodobacter capsulatus, AerR, which acts as a repressor under aerobic conditions [Dong, C., Elsen, S., Swem, L. R. & Bauer, C. E. (2002). J Bacteriol 184, 2805-2814]. The expression of the ppaA gene increases several-fold in response to a decrease in oxygen tension, suggesting that the PpaA protein is active under conditions of low or no oxygen. However, no discernible phenotype of a ppaA null mutant was observed under anaerobic conditions tested thus far. The photosystem gene repressor PpsR mediates repression of ppaA gene expression under aerobic conditions. Sequence analysis of PpaA homologues from several anoxygenic phototrophic bacteria revealed a putative corrinoid-binding domain. It is suggested that PpaA binds a corrinoid cofactor and the availability or structure of this cofactor affects PpaA activity.

Structural characterization of respiratory syncytial virus fusion inhibitor escape mutants: homology model of the F protein and a syncytium formation assay

Respiratory syncytial virus (RSV) is a ubiquitous human pathogen and the leading cause of lower respiratory tract infections in infants. Infection of cells and subsequent formation of syncytia occur through membrane fusion mediated by the RSV fusion protein (RSV-F). A novel in vitro assay of recombinant RSV-F function has been devised and used to characterize a number of escape mutants for three known inhibitors of RSV-F that have been isolated. Homology modeling of the RSV-F structure has been carried out on the basis of a chimera derived from the crystal structures of the RSV-F core and a fragment from the orthologous fusion protein from Newcastle disease virus (NDV). The structure correlates well with the appearance of RSV-F in electron micrographs, and the residues identified as contributing to specific binding sites for several monoclonal antibodies are arranged in appropriate solvent-accessible clusters. The positions of the characterized resistance mutants in the model structure identify two promising regions for the design of fusion inhibitors. (C) 2003 Elsevier Science (USA). All rights reserved.

New structure formation on gamma-irradiation of poly(chlorotrifluoroethylene)

The radiation chemistry of PCTFE at different temperatures has been studied. The polymer was irradiated under vacuum to absorbed doses of up to 1500 kGy. Three irradiation temperatures were chosen. These included ambient temperature, a temperature well above the T, and a temperature above the crystalline melting temperature. These were 298, 423 and 493 K, respectively. The formation of new structures was identified by solid-state FTIR and F-19 NMR. No branching was observed below the melting temperature, but branches were observed above the melting temperature. G-values for chain-end formation were 1.5 and 2.4 at room temperature and 423 K, respectively and the G-value for the formation of double bonds was found to be < 0.1. For the irradiations at 493 K, the G-values for the formation of chain ends, double bonds and branching points were 3.6, 0.2 and 0.5, respectively. The presence of long-chain branches within the polymer structure could not be proven for radiolysis at 493 K, but scission predominates and network formation does not occur upon irradiation. DSC studies of the polymers irradiated at ambient temperature were consistent with chain scission leading to an increase in the percentage crystallinity, as observed for other fluoropolymers. (C) 2003 Elsevier Science Ltd. All rights reserved.

Radical formation on gamma-radiolysis of poly [(methacrylic acid)-co-acrylonitri

The radicals formed on gamma-radiolysis of a series of copolymers of methacrylic acid and acrylonitrile have been investigated by ESR spectroscopy. This series of copolymers spanned the full composition range and the study was carried out at 77 K and ambient temperature. The radicals formed in the copolymers at 77 and 303 K were found to be similar to those found in the two homopolymers, but in the intermediate composition range the presence of acrylonitrile propagation radicals was also detected. These radicals were not observed to be formed in significant quantities on the radiolysis of polyacrylonitrile. They are believed to result from a scission of the main chain at methacrylic acid/acrylonitrile diad sequences following loss of the methacrylic acid carboxyl group. At 77 K, the copolymers with high methacrylic acid contents were found to be more sensitive to radical formation than the methacrylic acid homopolymer, but this enhanced sensitivity was not evident at ambient temperature, where the G-values for radical formation for the copolymers were slightly less than the values for the homopolymers. (C) 2003 Society of Chemical Industry.

Structural variations and formation constants of first-row transition metal complexes of biologically active aroylhydrazones

Iron chelators of the 2-pyridinecarbaldehyde isonicotinoylhydrazone (HPCIH) class show high potential for the treatment of iron overload diseases. In the present study, selected first-row transition metal (from Mn to Zn) complexes with HPCIH and 2-pyridinecarbaldehyde (4'-aminobenzoyl)hydrazone (HPCAH) were synthesised and characterised. Crystallography reveals that HPCAH exclusively forms bis complexes with divalent transition metals, with each ligand coordinating meridionally through its pyridine-N, imine-N and carbonyl-O atoms, forming distorted octahedral cis-MN4O2 complexes. Complexes of HPCIH were more varied and unpredictable, with metal/ligand ratios of 1:1, 1:2, 2:2 and 3:2 obtained with different metal ions. The isonicotinoyl ring N-atom in HPCIH was found to be an effective ligand, and this resulted in the varied metal/ligand ratios observed. The formation constants of divalent metal complexes with HPCIH were determined by potentiometric titrations and the values obtained were consistent with similar tridentate ligands and with the Irving-Williams order. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003).

Sistema de coleta on-line do Censo Escolar da Educa????o B??sica (Educacenso)

O Educacenso ?? um sistema eletr??nico de coleta de informa????es educacionais composto por um aplicativo web, que permite a coleta, migra????o e altera????o de dados educacionais das escolas em todo o territ??rio nacional, e por um banco de dados relacional, que armazena de forma sistem??tica todas estas informa????es. O Educacenso representa uma inova????o, pois se trata de um banco de dados ??nico, de base nacional, alimentado por dados e informa????es que v??m diretamente das escolas, por meio da internet. Constitui-se no mais completo cadastro de escolas, alunos e docentes do pa??s. A constru????o de um banco de dados com informa????es individualizadas amplia as possibilidades de comunica????o com outras bases de dados do governo federal. O novo desenho metodol??gico e a utiliza????o de recursos de tecnologia da informa????o permitiram ampliar a precis??o e a fidedignidade dos dados do Censo Escolar, o que possibilita realiza????o de ajustes na pol??tica educacional e maior efetividade do gasto p??blico com a educa????o b??sica

Planejamento participativo na implanta????o do sistema da concess??o on-line na Previd??ncia

Os Postos de Seguro Social do INSS processavam os dados dos segurados da Previd??ncia em lotes, acarretando demora na Concess??o de Benef??cios e perda de tempo por parte dos segurados, com muitas idas e vindas aos postos. As criticas aos dados eram realizadas uma vez por semana e em conseq????ncia os segurados eram obrigados a voltar ao posto para resolver as pend??ncias posteriormente informadas e at?? que os dados passassem pelas cr??ticas do computador central. Havia necessidade de implantar um novo sistema para melhorar o atendimento no INSS. Foi implementado no Paran?? um projeto piloto, desenvolvido pela Dataprev e a pedido de seu cliente INSS, denominado ???Concess??o de Benef??cios On Line???. Com a utiliza????o desta tecnologia, por exemplo, passou a ser poss??vel entrar com um pedido de aposentadoria e imprimir imediatamente a Carta de Concess??o, informando o valor e o banco em que ser??o feitos os pagamentos ao Segurado da Previd??ncia Social. O novo sistema ap??ia a melhoria no atendimento do segurado do INSS, porque permite informar ao Segurado imediatamente se o Benef??cio est?? concedido ou se h?? pend??ncias que devam ser atendidas

M??dulo 1 - atua????o do professor-tutor em organiza????es p??blicas: curso tutoria on-line em organiza????es p??blicas

Este documento trata de: a educa????o continuada do servidor p??blico, desenvolvimento de compet??ncias nas organiza????es p??blicas, o papel das escolas de governo na forma????o do servidor p??blico, a EaD como estrat??gia de educa????o continuada, educa????o a dist??ncia na Enap, bases de atua????o da cgead, o desenvolvimento das compet??ncias de tutoria

M??dulo 2 - o professor-tutor e as tecnologias: tutoria on-line em organiza????es p??blicas

Este documento trata de M??dulo 2 - o professor-tutor, Introdu????o, as tecnologias da intelig??ncia e o ciberespa??o, mapeando as tecnologias da educa????o a dist??ncia, ambientes virtuais de aprendizagem (AVA) e sistemas de gerenciamento de aprendizagem (SGA), o Moodle, compet??ncias tecnol??gicas da tutoria, refer??ncias, finalizando o m??dulo

M??dulo 3 - o professor-tutor e os aprendizes: tutoria on-line em organiza????es p??blicas

Este documento trata de m??dulo 3 - O professor-tutor e os aprendizes, objetivos do m??dulo, introdu????o, a evolu????o da educa????o a dist??ncia e as novas possibilidades de intera????o, o perfil do aluno da educa????o a dist??ncia, implica????es pr??ticas para o trabalho do professor-tutor, compet??ncias sociais do professor tutor da Enap, refer??ncias, finalizando o m??dulo

M??dulo 4 - o professor-tutor e a aprendizagem: tutoria on-line em organiza????es p??blicas

Este documento trata de M??dulo 4 - o professor-tutor e a aprendizagem, objetivos do m??dulo, introdu????o, articulando teorias e m??todos com o contexto educacional mais amplo, a perspectiva construtivista da aprendizagem, contribui????es da heutagogia e do conectivismo, implica????es para a atua????o do tutor, a avalia????o da aprendizagem, compet??ncias pedag??gicas do professor-tutor da Enap, refer??ncias, finalizando o m??dulo

M??dulo 5 - o professor-tutor e a institui????o: tutoria on-line em organiza????es p??blicas

Este documento trata de M??dulo 5 - o professor-tutor e a institui????o, objetivos do m??dulo, introdu????o, aprendizagem organizacional, comunidades de pr??tica, o profissional reflexivo, implica????es para a atua????o do professor-tutor, programa de forma????o de professores-tutores para educa????o continuada a dist??ncia, compet??ncias gerenciais do professor-tutor da Enap, refer??ncias, finalizando o m??dulo

Tutoria on-line em organiza????es p??blicas

Este documento trata de m??dulo 1 - atua????o do professor-tutor em organiza????es p??blicas, m??dulo 2 - o professor-tutor e as tecnologias, m??dulo 3 - o professor-tutor e os aprendizes, m??dulo 4 - o professor-tutor e a aprendizagem, m??dulo 5 - o professor-tutor e a institui????o

A educa????o on-line como estrat??gia para a forma????o do servidor p??blico brasileiro: o desenvolvimento de curso a dist??ncia para a melhor gest??o das transfer??ncias volunt??rias de recursos p??blicos

Este artigo relata a experi??ncia da ENAP com a educa????o on-line como estrat??gia para a forma????o do servidor p??blico brasileiro. ?? dado destaque ao desenvolvimento do curso a dist??ncia Gest??o de Conv??nios e de Contratos de Repasse para Convenentes, desenvolvido em parceria com a Casa Civil da Presid??ncia da Rep??blica e a Secretaria de Tecnologia e Log??stica da Informa????o do Minist??rio do Planejamento, Or??amento e Gest??o brasileiro. A iniciativa teve como objetivo contribuir para a melhor gest??o das transfer??ncias volunt??rias de recursos p??blicos no Brasil. Ao final s??o apresentadas reflex??es sobre a apropria????o de tecnologias de informa????o e de comunica????o em processos de forma????o de servidores p??blicos que se traduzem como investimentos para o ??xito da a????o governamental.