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Galactosidase Expression (galactosidase + expression)

Distribution by Scientific Domains

Life Sciences	75%

Selected Abstracts

Villin: A marker for development of the epithelial pyloric border

DEVELOPMENTAL DYNAMICS, Issue 1 2002
Evan M. Braunstein
Abstract In the adult gastrointestinal tract, the morphologic borders between esophagus and stomach and between stomach and small intestine are literally one cell thick. The patterning mechanisms that underlie the development of these sharp regional divisions from a once continuous endodermal tube are still obscure. In the embryonic endoderm of the developing gut, region-specific expression of certain genes (e.g., intestine-specific expression of the actin bundling protein villin) can be detected as early as 9.0 days post coitum, although the morphologic differentiation of the gut epithelium proper does not begin until 4 to 5 days later. By using a mouse model in which a ,-galactosidase marker has been inserted into the endogenous villin locus, we examined the development of the stomach/intestinal (pyloric) border during gut organogenesis. The data indicate that the border is not sharp from the outset. Rather, the initial border region is characterized by a decreasing gradient of villin/,-galactosidase expression that extends into the distal stomach. A sharp epithelial border of villin/,-galactosidase expression appears abruptly at day 16 and is further refined over the next 3 weeks to form the distinct one-cell-thick border characteristic of the adult. These results indicate that an important previously unrecognized patterning event occurs in the gut epithelium at 16 days; this event may define an epithelial compartment boundary between the stomach and the intestine. The villin/,-galactosidase mouse model characterized here provides an excellent substrate with which to further dissect the mechanisms involved in this patterning process. © 2002 Wiley-Liss, Inc. [source]

Dopamine and sensory tissue development in Drosophila melanogaster

DEVELOPMENTAL NEUROBIOLOGY, Issue 4 2001
Wendi Neckameyer
Abstract Dopamine is an important signaling molecule in the nervous system; it also plays a vital role in the development of diverse non-neuronal tissues in the fruit fly Drosophila melanogaster. The current study demonstrates that males depleted of dopamine as third instar larvae (via inhibition of the biosynthetic enzyme tyrosine hydroxylase) demonstrated abnormalities in courtship behavior as adults. These defects were suggestive of abnormalities in sensory perception and/or processing. Electroretinograms (ERGs) of eyes from adults depleted of dopamine for 1 day as third instar larvae revealed diminished or absent on- and off-transients. These sensory defects were rescued by the addition of L -DOPA in conjunction with tyrosine hydroxylase inhibition during the larval stage. Depletion of dopamine in the first or second larval instar was lethal, but this was not due to a general inhibition of proliferative cells. To establish that dopamine was synthesized in tissues destined to become part of the adult sensory apparatus, transgenic lines were generated containing 1 or 4 kb of 5, upstream sequences from the Drosophila tyrosine hydroxylase gene (DTH) fused to the E. coli ,-galactosidase reporter. The DTH promoters directed expression of the reporter gene in discrete and consistent patterns within the imaginal discs, in addition to the expected expression in gonadal, brain, and cuticular tissues. The ,-galactosidase expression colocalized with tyrosine hydroxylase protein. These results are consistent with a developmental requirement for dopamine in the normal physiology of adult sensory tissues. © 2001 John Wiley & Sons, Inc. J Neurobiol 47: 280,294, 2001 [source]

Estradiol-antagonistic activity of phenolic compounds from leguminous plants,

PHYTOTHERAPY RESEARCH, Issue 3 2008
B. Pinto
Abstract Natural flavonoids are currently receiving much attention because of their estrogenic and antiestrogenic properties. Six isoflavones (isoprunetin, isoprunetin 7- O - , - d -glucopyranoside, isoprunetin 4,,7-di- O - , - d -glucopyranoside, genistein, genistein 7-O- , - d -glucopyranoside, daidzein), four flavones (luteolin, luteolin 7-O- , - d -glucopyranoside, luteolin 4,-O- , - d -glucopyranoside, licoflavone C), isolated from Genista morisii and G. ephedroides (two Leguminosae plants of the Mediterranean area) together with two structurally related pterocarpans, bitucarpin A and erybraedyn C, isolated from Bituminaria bituminosa (Leguminosae), were tested for the antagonist activity by a yeast based estrogen receptor assay (Saccharomyces cerevisiae RMY326 ER-ERE). Most compounds inhibited the estradiol-induced transcriptional activity in a concentration dependent manner. In particular, for the flavone luteolin 77% inhibition of the induced , -galactosidase activity was observed. Interestingly, licoflavone C exhibited a dose-dependent antagonistic activity at concentrations up to 10,4 m, but stimulated , -galactosidase expression at higher concentrations resulting in a U-shaped-like dose-response curve. Copyright © 2007 John Wiley & Sons, Ltd. [source]

Nuclear-targeted minicircle to enhance gene transfer with non-viral vectors in vitro and in vivo

THE JOURNAL OF GENE MEDICINE, Issue 6 2006
Laurence Vaysse
Abstract Background To develop more efficient non-viral vectors, we have previously described a novel approach to attach a nuclear localisation signal (NLS) to plasmid DNA, by generating a fusion protein between the tetracycline repressor protein TetR and an SV40 NLS peptide (TetR-NLS). The high affinity of TetR for the DNA sequence tetO is used to bind the NLS to DNA. We have now investigated the ability of this system displaying the SV40 NLS or HIV-1 TAT peptide to enhance nuclear import of a minimised DNA construct more suitable for in vivo gene delivery: a minicircle. Methods We have produced a new LacZ minicircle compatible with the TetR system. After transfection of the minicircle in combination with TetR-NLS or TetR-TAT using different transfection agents, we first measured ,-galactosidase activity in vitro. We then used a special delivery technique, in which DOTAP/cholesterol liposomes and DNA/protein complexes are sequentially injected intravenously, to evaluate the activity of this system in vivo. Results In vitro results showed a 30-fold increase in transfection efficiency of the nuclear-targeted minicircle compared to normal plasmid lipofection. Results on cell cycle arrested cells seem to indicate a different mechanism between the TetR-NLS and TetR-TAT. Finally, we demonstrate a more than 6-fold increase in ,-galactosidase expression in the mouse lung using the minicircle and the TetR-TAT protein. This increase is specific for the peptide sequence and is not observed with the control protein TetR. Conclusions Our results indicate that the combination of a minicircle DNA construct with a TetR nuclear-targeting system is able to potentiate gene expression of non-viral vectors. Copyright © 2006 John Wiley & Sons, Ltd. [source]