Targeted green-red photoconversion of EosFP, a fluorescent marker protein

EosFP is a novel fluorescent protein from the stony coral Lobophyllia hemprichii. Its gene was cloned in Escherichia coli to express the tetrameric wild-type protein. The protein emits strong green fluorescence (516 nm) that shifts toward red (581 nm) upon near-ultraviolet irradiation at ?390 nm due to a photo-induced modification that involves a break in the peptide backbone next to the chromophore. Using site-directed mutagenesis, dimeric (d1EosFP, d2EosFP) and monomeric (mEosFP) variants were produced with essentially unaltered spectroscopic properties. Here we present a spectroscopic characterization of EosFP and its variants, including room- and low-temperature spectra, fluorescence lifetime determinations, two-photon excitation and two-photon photoconversion. Furthermore, by transfection of a human cancer (HeLa) cell with a fusion construct of a mitochondrial targeting sequence and d2EosFP, we demonstrate how localized photoconversion of EosFP can be employed for resolving intracellular processes

Genetic transformation of Drosophila willistoni using piggyBac transposon and GFP

Studies were carried out on the use of piggyBac transposable element as vector and the green fluorescent protein (EGFP) from the jellyfish, Aquorea victoria, as a genetic marker for the transformation of Drosophila willistoni. Preblastoderm embryos of D. willistoni white mutant were microinjected with a plasmid containing the EGFP marker and the piggyBac ITRs, together with a helper plasmid containing the piggyBac transposase placed under the control of the D. melanogaster hsp70 promoter. G0 adults transformants were recovered at a frequency of approximately 67%. Expression of EGFP in larvae, pupae and adults was observed up to the third generation, suggesting that this transposon was not stable in D. willistoni. Transformed individuals displayed high levels of EGFP expression during larvae and adult stages in the eye, abdomen, thorax and legs, suggesting a wide expression pattern in this species than reported to other species of Drosophilidae.<br>Descrevemos neste trabalho a transformação genética de Drosophila willistoni empregando o elemento transponível piggyBac como vetor e o gene EGFP (green fluorescent protein ) retirado da água-viva Aquorea victoria, como marcador de transformação. Embriões de D. willistoni em estágio pré-blastoderme, mutantes para o gene white, foram microinjetados com plasmídio contendo o marcador EGFP e as regiões ITRs do transposon piggyBac concomitantemente com um plasmídio auxiliar possuindo o gene da transposase de piggyBac sobre o controle do promotor do gene hsp70 de Drosophila melanogaster. Adultos transformantes Go foram gerados em uma taxa de 67%. A expressão de GFP em larvas, pupas e adultos foi observada somente até a terceira geração, sugerindo que este transposon não é estável em D. willistoni. Os indivíduos transformados exigem um alto nível de expressão de EGFP durante os estágios de larva e, também em adultos o gene marcador é expresso nos olhos, abdome, tórax e patas, mostrando um padrão de expressão mais amplo nesta espécie do que o registrado para outros drosofilídeos