RESUMO
Chemokine receptors are not only able to bind chemokines but, together with CD4, they serve as an entry door for the human immunodeficiency virus type 1 (HIV-1). The signalling capacity of chemokine receptors, which is of fundamental importance for chemokine-induced chemotaxis, is not used by HIV-1 to enter a target cell, nor by chemokines or chemokine-derived ligands to inhibit viral entry. In addition, an ill-defined signal triggered by chemokines can, under some circumstances, lead to an increase in HIV-1 expression. We show here that, in infected cells, exposure to SDF-1 leads to an increased expression of a X4 strain of HIV-1. A similar increase can be induced by an N-terminal peptide of SDF-1 which had previously been shown to elicit an intracellular calcium response and to inhibit the entry of X4 strains of HIV-1. We demonstrate the involvement of extracellular signal-regulated kinases (ERK) in this phenomenon. SDF-1 activates ERK-1 and ERK-2 in Jurkat cells. In HeLa cells, ERK-2 only is activated by SDF-1 or by a SDF-derived peptide. This ERK activation can be blocked by pertussis toxin and by the MEK inhibitor U0126. Most importantly, SDF-1-dependent HIV-1 expression is abolished by pretreating the cells with pertussis toxin or with U0126. The consequences of this SDF-1-induced, ERK-dependent modulation of HIV-1 expression in infected cells may have a clinical relevance for eradicating latent viruses.
Assuntos
Fármacos Anti-HIV/farmacologia , Quimiocinas CXC/farmacologia , HIV-1/fisiologia , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Replicação Viral/efeitos dos fármacos , Butadienos/farmacologia , Antígenos CD4/genética , Antígenos CD4/fisiologia , Cálcio/metabolismo , Ciclo Celular , Quimiocina CXCL12 , Ativação Enzimática , Inibidores Enzimáticos/farmacologia , Repetição Terminal Longa de HIV/genética , HIV-1/efeitos dos fármacos , HIV-1/genética , Células HeLa , Humanos , Células Jurkat , Nitrilas/farmacologia , Fragmentos de Peptídeos/farmacologia , Receptores CXCR4/fisiologia , Transcrição Gênica , TransfecçãoRESUMO
Recently, the presence of human immunodeficiency virus type 1 (HIV-1) RNA transcripts with negative-strand polarity has been shown in tissue culture models of acute and persistently infected cells. One of these transcripts encodes a 189 amino acid open reading frame. This highly conserved antisense sequence is complementary to the structured Rev-responsive element and extends through the cleavage site of the Env protein. We tested the ability of this antisense RNA to modulate HIV-1 replication and the mRNA profile when expressed stably or transiently in several cell types. Different cell lines and PBLs were transduced by retroviral vectors producing antisense RNA and were then challenged by HIV infection. We have shown that the endogenously expressed antisense RNA containing the natural open reading frame inhibits HIV-1(IIIB) and HIV-1(NDK) replication in these cells. The level of inhibition varied according to the cells, but was significant in all cases. The production of HIV-1 (BRU, IIIB, NDK) mRNAs was also significantly decreased. HIV-2 replication was not inhibited by expression of the antisense RNA. Our results also suggest that this inhibitory effect is due to the antisense RNA and not to the protein which is encoded by this sequence.
Assuntos
HIV-1/crescimento & desenvolvimento , RNA Antissenso/genética , RNA Viral/genética , Replicação Viral , Células Cultivadas , Regulação Viral da Expressão Gênica , Produtos do Gene env/genética , Genes env , HIV-1/genética , Humanos , Fases de Leitura Aberta , RNA Mensageiro/genética , Especificidade da EspécieRESUMO
An integrated hepatitis B virus (HBV) DNA has been identified in a human neuroblastoma, cloned and sequenced. The integrated HBV DNA is not rearranged, although a 480-bp fragment is deleted. The integrated viral DNA covers the C gene fragment, the region of Pre-S and S, and the 3'-truncated X gene.
Assuntos
DNA Viral/análise , Vírus da Hepatite B/isolamento & purificação , Neuroblastoma/virologia , Integração Viral , Sequência de Bases , Clonagem Molecular , DNA Viral/genética , Vírus da Hepatite B/genética , Humanos , Dados de Sequência MolecularRESUMO
PCR is a highly sensitive, convenient and rapid method for detection of viral DNA in fixed tissue samples which allows one to analyse the material from the pathology files, mainly biopsies. PCR in a fixed material requires larger amounts of DNA-polymerase and longer duration of every stage of thermo-cycles compared to PCR in the purified DNA samples.
