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F Falciani

Publications and source records attributed to F Falciani.

14 recordsLinked to original sources
PubMed2006

Expression analysis of immune response genes of Müller cells infected with Toxoplasma gondii.

PURPOSE: To investigate changes in immune response genes following Toxoplasma gondii infection of Müller cells. METHODS: Human Müller cells were infected or mock infected with two strains of T. gondii (RH and Prugniaud). RNA and supernatants were collected from infected and uninfected cells at 2 and 24 h. RNA from the two time points were compared using a custom made DNA microarray. Real time PCR or human cytokine antibody array was used to confirm up-regulation of immune molecules. RESULTS: Gene expression in infected cells showed up-regulation of CCL2, IL-6, CXCL8, and CXCL2. CCL2 and CXCL2 gene expression was confirmed by real time PCR. IL-6 and CXCL8 protein production was confirmed by a cytokine antibody array. IL-4 production was observed by cytokine antibody array but not by DNA microarray. In contrast, infection with T. gondii did not induce interferon-gamma (IFNgamma) and IL-12 expression, molecules conventionally associated with the inter-conversion of tachyzoite to bradyzoite. CONCLUSION: These results indicate that while in vitro infected Müller cells may be capable of inducing an immune response by attracting blood-borne leucocytes, they do not appear able to directly control the proliferation of T. gondii.

Animals↗
PubMed2003

Identification of differentially expressed genes in coronary atherosclerotic plaques from patients with stable or unstable angina by cDNA array analysis.

The composition of atherosclerotic plaques is a crucial factor in determining rupture, thrombosis and clinical events. In this study, we analyzed gene expression in coronary plaques from patients with stable or unstable angina using gene arrays. Total RNA was extracted from eight plaques collected by therapeutic directional coronary atherectomy. cDNA probes, generated by amplification, were hybridized to nylon arrays containing 482 genes. Here we report the results for the inflammation, adhesion and hemostasis subsets. Many genes not previously associated with atherosclerosis, such as the lymphocyte adhesion molecule MadCAM, were expressed in the plaques. anova analysis showed higher tissue factor (TF) expression in unstable angina samples. Five genes were expressed at lower levels in unstable angina samples: anticoagulant protein S, cyclooxygenase (COX)-1, interleukin (IL)-7 and chemokines monocyte chemotactic protein (MCP)-1 and -2. Gene arrays provide a new approach to study plaque composition and identify candidate markers of plaque instability.

Angina Pectoris↗
PubMed2001

Methods and approaches in the analysis of gene expression data.

The application of high-density DNA array technology to monitor gene transcription has been responsible for a real paradigm shift in biology. The majority of research groups now have the ability to measure the expression of a significant proportion of the human genome in a single experiment, resulting in an unprecedented volume of data being made available to the scientific community. As a consequence of this, the storage, analysis and interpretation of this information present a major challenge. In the field of immunology the analysis of gene expression profiles has opened new areas of investigation. The study of cellular responses has revealed that cells respond to an activation signal with waves of co-ordinated gene expression profiles and that the components of these responses are the key to understanding the specific mechanisms which lead to phenotypic differentiation. The discovery of 'cell type specific' gene expression signatures have also helped the interpretation of the mechanisms leading to disease progression. Here we review the principles behind the most commonly used data analysis methods and discuss the approaches that have been employed in immunological research.

Classification↗
PubMed2000

The comparison of gene expression from multiple cDNA libraries.

We describe a method for comparing the abundance of gene transcripts in cDNA libraries. This method allows for the comparison of gene expression in any number of libraries, in a single statistical analysis, to identify differentially expressed genes. Such genes may be of potential biological or pharmaceutical relevance. The formula that we derive is essentially the entropy of a partitioning of genes among cDNA libraries. This work goes beyond previously published analyses, which can either compare only two libraries, or identify a single outlier in a group of libraries. This work also addresses the problem of false positives associated with repeating the test on many thousands of genes. A randomization procedure is described that provides a quantitative measure of the degree of belief in the results; the results are further verified by considering a theoretically derived large deviations rate for the test statistic. As an example, the analysis is applied to four prostate cancer libraries from the Cancer Genome Anatomy Project. The analysis identifies biologically relevant genes that are differentially expressed in the different tumor cell types.

Gene Expression Profiling↗
PubMed1996

Class 3 Hox genes in insects and the origin of zen.

We have cloned, from a beetle and a locust, genes that are homologous to the class 3 Hox genes of vertebrates. Outside the homeobox they share sequence motifs with the Drosophila zerknüllt (zen) and z2 genes, and like zen, are expressed only in extraembryonic membranes. We conclude that the zen genes of Drosophila derive from a Hox class 3 sequence that formed part of the common ancestral Hox cluster, but that in insects this (Hox) gene has lost its role in patterning the anterio-posterior axis of the embryo, and acquired a new function. In the lineage leading to Drosophila, the zen genes have diverged particularly rapidly.

Amino Acid Sequence↗
PubMed1994

Molybdenum(VI) salts convert the xanthine oxidoreductase apoprotein into the active enzyme in mouse L929 fibroblastic cells.

The mouse L929 fibroblastic cell line presents low, but detectable, levels of the mRNA encoding xanthine oxidoreductase under basal conditions, and it responds to type I and type II interferons by inducing the expression of the transcript [Falciani, Ghezzi, Terao, Cazzaniga, and Garattini (1992) Biochem. J. 285, 1001-1008]. This cell line, however, does not show any detectable amount of xanthine oxidoreductase enzymic activity, either before or after treatment with the cytokines. Molybdenum(VI) salts, in the millimolar range, are capable of activating xanthine oxidoreductase in L929 cells both under basal conditions and after treatment with interferon-alpha. The increase is observed in mouse L929 as well as in clones derived from it, but not in many other human and mouse cell lines. The induction observed in L929 cells is post-translational in nature and it is insensitive to cycloheximide, indicating that the molybdenum ion converts a pool of inactive xanthine oxidoreductase apoenzyme into its holoenzymic form. When grown in the absence of sodium molybdate, the L929 cell line has undetectable intracellular levels of the molybdenum cofactor, since the cell extracts are unable to complement the nitrate reductase defect of the nit-1 mutant of Neurospora crassa. L929 cells grown in the presence of millimolar concentrations of sodium molybdate, however, become competent to complement the nit-1 defect. L929 cells accumulate molybdenum ion inside the intracellular compartment as efficiently as TEnd cells, a mouse endothelial cell line that expresses xanthine oxidoreductase activity both under basal conditions and after treatment with interferon-gamma, suggesting that L929 cells have a defect in one or more of the metabolic steps leading to the synthesis of the molybdenum cofactor.

3T3 Cells↗
PubMed1994

Dax, a locust Hox gene related to fushi-tarazu but showing no pair-rule expression.

We describe an unusual Antennapedia class homeobox gene from the grasshopper Schistocerca gregaria (Orthoptera, African Plague Locust). Its sequence is not sufficiently similar to that of any other insect Hom-Hox gene to identify it unambiguously, but short conserved elements suggest a relationship to the segmentation gene fushi-tarazu, (ftz). We term it Sg Dax (divergent Antennapedia class homeobox gene). Antibodies raised against the protein encoded by this gene reveal two phases of expression during embryogenesis. In the early embryo, it is a marker for the posterior part of the forming embryonic primordium, and subsequently for the posterior part of the growing germ band. In older embryos, it labels a subset of neural precursor cells in each trunk segment, very similar to that defined by the expression of fushi tarazu (ftz) in Drosophila. We suggest that Schistocerca Dax and Drosophila ftz are homologous members of a gene family whose members are diverging relatively rapidly, both in terms of sequence and role in early development.

Amino Acid Sequence↗
PubMed1994

The evolving role of Hox genes in arthropods.

Comparisons between Hox genes in different arthropods suggest that the diversity of Antennapedia-class homeotic genes present in modern insects had already arisen before the divergence of insects and crustaceans, probably during the Cambrian. Hox gene duplications are therefore unlikely to have occurred concomitantly with trunk segment diversification in the lineage leading to insects. Available data suggest that domains of homeotic gene expression are also generally conserved among insects, but changes in Hox gene regulation may have played a significant role in segment diversification. Differences that have been documented alter specific aspects of Hox gene regulation within segments and correlate with alterations in segment morphology rather than overt homeotic transformations. The Drosophila Hox cluster contains several homeobox genes that are not homeotic genes--bicoid, fushi-tarazu and zen. the role of these genes during early development has been studied in some detail. It appears to be without parallel among the vertebrate Hox genes. No well conserved homologues of these genes have been found in other taxa, suggesting that they are evolving faster than the homeotic genes. Relatively divergent Antp-class genes isolated from other insects are probably homologues of fushi-tarazu, but these are almost unrecognisable outside of their homeodomains, and have accumulated approximately 10 times as many changes in their homeodomains as have homeotic genes in the same comparisons. They show conserved patterns of expression in the nervous system, but not during early development.

Animals↗
PubMed1993

Cytokine induction of haem oxygenase mRNA in mouse liver. Interleukin 1 transcriptionally activates the haem oxygenase gene.

Accumulation of the mRNA coding for haem oxygenase (HO, EC 1.14.99.3) was stimulated by treating mice with endotoxin (lipopolysaccharide, LPS; 20 micrograms/mouse intraperitoneally), suggesting that haem catabolism is a target of infection and inflammation in vivo. Therefore various cytokines, possible mediators for the biological responses to LPS, were administered intraperitoneally to mice, and the levels of HO mRNA were measured by Northern-blotting analysis using the rat HO cDNA as a probe [Shibahara, Müller, Taguchi and Yoshida (1985) Proc. Natl. Acad. Sci. U.S.A. 82, 7865-7869]. Marked induction of HO mRNA was observed 2 h after administration of interleukin 1 (IL-1) (34-fold) and tumour necrosis factor (19.5-fold) (5 micrograms/mouse), whereas interleukin 6 (6.2 micrograms/mouse) was much less active (3.5-fold) and interleukin 2 (25 micrograms/mouse) and interferon-gamma (3 micrograms/mouse) were ineffective. HO mRNA induced by the cytokines of LPS accumulated rapidly (maximum at 1-2 h after administration), preceding the elevation of HO enzymic activity. Treatment of mice with IL-1 stimulated the transcription of the HO gene by 4-fold, as assessed by in vitro nuclear-run-on assay. These results indicate that enzymic haem catabolism in the liver is a process inducible in vivo by inflammatory cytokines, which up-regulate HO synthesis at the transcriptional level. Increased removal of haem might be part of the protective mechanisms elicited by the acute-phase response, possibly to reduce the pro-oxidant state of the cell.

Animals↗
PubMed1992

Regulation of the 202 gene expression by interferons in L929 cells.

Type I and II interferons (IFNs) stimulate the expression of the 202 and 2'-5' oligoadenylate synthetase (OASE) genes in L929, NIH 3T3 and LM-TK- fibroblastic cell lines. In two other cell lines, B16 melanoma and F9 teratocarcinoma, these cytokines induce OASE but not the 202 mRNA. In L929 cells, IFN-alpha induces the 202 mRNA at concentrations between 10 and 10(3) units/ml. To achieve maximal induction of the 202 mRNA, continuous exposure of L929 cells to IFN-alpha is necessary, whereas 30 minutes of exposure are sufficient to trigger maximal upregulation of the OASE transcript. The induction of the 202 mRNA is the consequence of both transcriptional and post-transcriptional events. Cycloheximide, a known inhibitor of protein synthesis, does not block the induction of 202 mRNA by IFN-alpha, demonstrating that new protein synthesis is not required for this effect. Protein kinase C, arachidonic acid metabolism via the cyclooxygenase or the lipoxygenase pathways and cAMP are not involved as second messengers in the induction of the 202 mRNA by IFN-alpha in L929 cells.

2',5'-Oligoadenylate Synthetase↗
PubMed1992

Interferons induce xanthine dehydrogenase gene expression in L929 cells.

Human interferon-alpha A/D (Bg/II) (IFN-alpha A/D) and mouse interferon-gamma (IFN-gamma) are shown to induce xanthine dehydrogenase (XD) mRNA in L929 fibroblastic cells. XD mRNA accumulation after IFN-alpha A/D treatment is relatively fast, being already evident after 4 h and reaching its maximum after 24 h. IFN-alpha A/D is active in inducing XD mRNA at 0.1 unit/ml and it is maximally active at 10(3) units/ml. The half-life of the XD message is unaffected by IFN-alpha A/D treatment, whereas the transcriptional activity of the XD gene and the concentrations of XD heterogeneous nuclear RNA are increased by 2- and 6-fold respectively. The effect of IFN-alpha A/D on XD mRNA is insensitive to cycloheximide, suggesting that protein synthesis de novo is not required. Experiments conducted with specific inhibitors suggest that protein kinase C, cyclic AMP and arachidonic acid metabolites derived from lipoxygenase or cyclooxygenase do not act as second-messenger molecules in the induction of XD mRNA by IFN-alpha A/D. XD mRNA is also induced in NIH3T3 fibroblastic cells, but not in F9 teratocarcinoma or B16 melanoma cells after treatment with IFN-alpha A/D. NIH3T3 are the only cells so far tested that have detectable XD and xanthine oxidase activities under basal conditions and after IFN-alpha A/D treatment, although their responsiveness to the cytokine is much less than that observed in L929 cells.

Bucladesine↗
PubMed1992

Molecular cloning of a cDNA coding for mouse liver xanthine dehydrogenase. Regulation of its transcript by interferons in vivo.

The cDNA coding for xanthine dehydrogenase (XD) is isolated from mouse liver mRNA by cross-hybridization with a DNA fragment of the Drosophila melanogaster homologue. Two lambda bacteriophage overlapping clones represent the copy of a 4538-nucleotide-residue-long transcript with an open reading frame of 4005 nucleotide residues, coding for a putative polypeptide of 1335 amino acid residues. Comparison of the deduced amino acid sequence of the mouse XD with those of the Drosophila and the rat homologues shows a high conservation of this protein (55% identity between mouse and Drosophila, and 94% identity between mouse and rat). RNA blotting analysis demonstrates that interferon-alpha (IFN-alpha) and its inducers, i.e. poly(I).poly(C), bacterial lipopolysaccharide (LPS) and tilorone (2,7-bis-[2-(diethylamino)ethoxy]fluoren-9-one), increase the expression of XD mRNA in liver. Poly(I).poly(C) also induces XD mRNA in several other tissues in vivo. Protein synthesis de novo is not required for the elevation of XD mRNA after IFN-alpha treatment, since cycloheximide does not block the induction. The elevation of XD mRNA concentration is relatively fast and precedes the induction of both XD and xanthine oxidase (XO) enzymic activities.

Amino Acid Sequence↗
PubMedDate not supplied

Maternal expression and early zygotic regulation of the Hox3/zen gene in the grasshopper Schistocerca gregaria.

In insects, a key step in the early patterning of the egg is to distinguish the primordium of the embryo proper from those regions that will form extra-embryonic membranes. In Drosophila, where these processes are well understood, the structure of the extra-embryonic membranes is highly derived. The distinct amnion and serosa typical of lower insects is replaced by a single, fused, and much reduced membrane, the amnioserosa, which never secretes an embryonic cuticle. We have used the Zen gene as a marker to study the formation of the extra-embryonic membranes, and other aspects of early embryonic patterning, in the grasshopper Schistocerca gregaria (African Plague Locust). Zen genes are derived from Hox genes, but in Drosophila they appear to have lost any role in patterning the A/P axis of the embryo; instead, they are involved in D/V patterning and the specification of the extra-embryonic membranes. We show that the Schistocerca zen gene is expressed during embryogenesis in three distinct phases. The first of these is during cleavage, when Sgzen is transiently expressed in all energids that reach the cell surface. The second phase of expression initiates in a ring of "necklace cells" that surround the forming embryo, and demarcate the boundary between the amnion and serosa. This leads to expression throughout the serosa. The final phase of expression is in the amnion, after this has separated from the serosa. This complex pattern implies that the role of Sgzen in Schistocerca is not limited solely to the specification of cell identity in the extra-embryonic membranes. We also report that the Schistocerca zen gene is expressed maternally, unlike its Drosophila and Tribolium counterparts. A distinct maternal transcript, and maternal Zen protein, accumulate in the developing oocyte from early post-meiotic stages. They remain uniformly distributed in the oocyte cytoplasm until late vitellogenic stages, when the protein and RNA become somewhat concentrated at the egg cortex and in the posterior polar cap of the oocyte, probably by passive exclusion from the yolk. The cytoplasmic localization of Sgzen protein in the oocyte, and at some stages during embryogenesis, implies that nuclear exclusion of this transcription factor is specifically controlled.

Animals↗