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Leonardo D'Aiuto

Publications and source records attributed to Leonardo D'Aiuto.

5 recordsLinked to original sources
PubMed2006

Evidence of the capability of the CMV enhancer to activate in trans gene expression in mammalian cells.

Studies have reported that an enhancer can act in trans when artificially, noncovalently bridged to the promoter by a protein-linked biotin:streptavidin complex, or when an enhancer and a promoter are located on separate concatenated plasmids. To investigate such transactivation in mammalian cells, we constructed CMV promoter-enhancer mutants driving the expression of the EGFP reporter gene and transfected cultured cells with various combinations of the mutant PCR products; results were analyzed using fluorescence microscopy and flow cytometry. Our results show that the CMV enhancer can stimulate transcription in trans, even in the absence of physical association of the enhancer and promoter. Furthermore, we show that the transactivation of the CMV enhancer can be strengthened by the histone deacetylase inhibitor sodium butyrate. Finally, we provide evidence that the CMV enhancer can influence, in trans, the activity of heterologous promoters. Although different mechanisms may lead to transcriptional activation when the CMV enhancer is not covalently linked to the promoter, our results suggest that the main mechanism resembles the process of transfection and may be important for gene regulation. These findings may have implications in understanding the processes that underlie gene therapy because of the potential alteration of endogenous gene expression.

Animals↗
PubMed2003

Effects of a SARS-associated coronavirus vaccine in monkeys.

The causative agent of severe acute respiratory syndrome (SARS) has been identified as a new type of coronavirus. Here, we have investigated the ability of adenoviral delivery of codon-optimised SARS-CoV strain Urbani structural antigens spike protein S1 fragment, membrane protein, and nucleocapsid protein to induce virus-specific broad immunity in rhesus macaques. We immunised rhesus macaques intramuscularly with a combination of the three Ad5-SARS-CoV vectors or a control vector and gave a booster vaccination on day 28. The vaccinated animals all had antibody responses against spike protein S1 fragment and T-cell responses against the nucleocapsid protein. All vaccinated animals showed strong neutralising antibody responses to SARS-CoV infection in vitro. These results show that an adenoviral-based vaccine can induce strong SARS-CoV-specific immune responses in the monkey, and hold promise for development of a protective vaccine against the SARS causal agent.

Adenoviridae↗
PubMed2003

Retrofitting BACs with G418 resistance, luciferase, and oriP and EBNA-1 - new vectors for in vitro and in vivo delivery.

BACKGROUND: Bacterial artificial chromosomes (BACs) have been used extensively for sequencing the human and mouse genomes and are thus readily available for most genes. The large size of BACs means that they can generally carry intact genes with all the long range controlling elements that drive full levels of tissue-specific expression. For gene expression studies and gene therapy applications it is useful to be able to retrofit the BACs with selectable genes such as G418 resistance, reporter genes such as luciferase, and oriP/EBNA-1 from Epstein Barr virus which allows long term episomal maintenance in mammalian cells. RESULTS: We describe a series of retrofitting plasmids and a protocol for in vivo loxP/Cre recombination. The vector pRetroNeo carries a G418 resistance cassette, pRetroNeoLuc carries G418 resistance and a luciferase expression cassette, pRetroNeoLucOE carries G418 resistance, luciferase and an oriP/EBNA-1 cassette and pRetroNeoOE carries G418 resistance and oriP/EBNA-1. These vectors can be efficiently retrofitted onto BACs without rearrangement of the BAC clone. The luciferase cassette is expressed efficiently from the retrofitting plasmids and from retrofitted BACs after transient transfection of B16F10 cells in tissue culture and after electroporation into muscles of BALB/c mice in vivo. We also show that a BAC carrying GFP, oriP and EBNA-1 can be transfected into B16F10 cells with Lipofectamine 2000 and can be rescued intact after 5 weeks. CONCLUSION: The pRetro vectors allow efficient retrofitting of BACs with G418 resistance, luciferase and/or oriP/EBNA-1 using in vivo expression of Cre. The luciferase reporter gene is expressed after transient transfection of retrofitted BACs into cells in tissue culture and after electroporation into mouse muscle in vivo. OriP/EBNA-1 allows stable maintenance of a 150-kb BAC without rearrangement for at least 5 weeks.

Animals↗
PubMedDate not supplied

Generation of a telomere-based episomal vector.

We have developed a telomere-based episome by large-scale amplification in Escherichia coli cells. This episome consists of a PAC vector in which a 6 Kb sequence, containing an array of telomeric repeats spaced by a synthetic sequence, is tandemly repeated by large-scale multimerization in E. coli. After transfection in human HT1080 cells, the construct, called clone 106, was able to persist in episomal form or integrated into some endogenous chromosomes. Integrations occurred exclusively at the telomeres. Episomes were still present in HT1080 cells after more than 100 days in the absence of selection. Integrations of clone 106 into the telomeric regions were retained only under selective conditions, and when the selection was removed the construct was progressively eliminated from the chromosome. The long-term maintenance of clone 106 into human cells as an episome and its ability to integrate transiently into the telomeres of the host chromosomes suggest that this PAC-based episome is potentially a good candidate vector for gene therapy applications.

Cell Line, Tumor↗