PubMed Health⌕ Search

Biomedical subjects

E Borrelli

Publications and source records attributed to E Borrelli.

At least 73 records · Page 4Linked to original sources
PubMed1991

CREM gene: use of alternative DNA-binding domains generates multiple antagonists of cAMP-induced transcription.

We isolated a gene from a mouse pituitary cDNA library that encodes a protein highly homologous to nuclear factor CREB, an activator of cAMP-responsive promoter elements (CREs). We demonstrate that while CREB is expressed uniformly in several cell types, this gene, termed CREM, shows cell-specific expression. CREM has a remarkable organization, since down-stream of the stop codon there is a second, out-of-frame DNA-binding domain. Using PCR and RNAase protection analysis, we have identified three mRNA isoforms that appear to be obtained by differential cell-specific splicing. Sequencing of the isoforms demonstrated alternative usage of the two DNA-binding domains. CREM proteins reveal the same efficiency and specificity of binding to CRE sequences as CREB, but in contrast to CREB, CREM acts as a down-regulator of cAMP-induced transcription.

Amino Acid Sequence↗
PubMed1991

Differential expression of the mouse D2 dopamine receptor isoforms.

We have identified and characterized the cDNAs corresponding to the mouse D2 dopamine receptors. We show that in the mouse the D2 dopamine receptor is found in two forms, generated by alternative splicing of the same gene, mRNA distribution analysis of areas expressing the D2 receptors shows that the larger form is the most abundant, except in the brain stem where the shorter form is predominant. Membranes of mammalian cells transiently transfected with both forms of D2 receptor bind [3H]spiperone with a high affinity.

Amino Acid Sequence↗
PubMed1991

Inhibition by methylprednisolone of leukocyte-induced pulmonary damage.

BACKGROUND AND METHODS: The purpose of this study was twofold: the development of a chronic model of leukocyte-mediated pulmonary injury and the evaluation of the protective effects of methylprednisolone. Rabbits were inoculated ip with zymosan. Blood gases and circulating leukocytes were evaluated. Survivors were killed on day 10 for microscopic studies and for the evaluation of lung lipid peroxidation through the by-product malondialdehyde. RESULTS: Intraperitoneal zymosan resulted in a marked decrease of Pao2 and circulating leukocytes, and increased cellularity of alveolar septa, interstitial edema, and increased lung malondialdehyde. Pulmonary damage was partially prevented when methylprednisolone was administered before zymosan inoculation, but not when methylprednisolone was given 24 hr later. CONCLUSIONS: The authors conclude that a local nonseptic inflammatory stimulus may provoke remote changes to the lungs and that methylprednisolone may counteract the process only if it is administered before or very early after the onset of inflammation.

Animals↗
PubMed1990

Cloning and characterization of a Drosophila tyramine receptor.

Receptors for biogenic amines such as dopamine, serotonin and epinephrine belong to the family of receptors that interact with G proteins and share a putative seven transmembrane domain structure. Using a strategy based on nucleotide sequence homology between the corresponding genes, we have isolated Drosophila cDNA clones encoding a new member of the G protein-coupled receptor family. This protein exhibits highest homology to the human alpha 2 adrenergic receptors, the human 5HT1A receptor and a recently cloned Drosophila serotonin receptor. The corresponding mRNA is found predominantly in adult Drosophila heads. Membranes from mammalian cells expressing this receptor displayed high affinity binding sites for [3H]yohimbine, an alpha 2 adrenergic receptor antagonist (Kd = 4.45 x 10(-9) M). Tyramine was the most efficient of the putative Drosophila neurotransmitters at displacing [3H]yohimbine binding (EC50 = 1.25 x 10(-6) M). Furthermore tyramine induced an inhibition of adenylate cyclase activity in NIH 3T3 cells expressing this receptor. The Drosophila tyramine receptor that we have isolated might therefore be an invertebrate equivalent of the mammalian alpha 2 adrenergic receptors.

Amino Acid Sequence↗
PubMed1990

Lipid peroxidation and lung ultrastructural changes in an experimental model of leukocyte-mediated pulmonary injury.

The aim of this study was to study ultrastructural changes and lipid peroxidation in rabbits lung after massive complement activation and leukocyte aggregation. A prolonged and massive leukocyte activation was induced by intraperitoneal inoculation of zymosan suspected in paraffin. Fifteen animals (group 3) were given 0.6 g/kg of zymosan, 22 animals (group 2) received 1 g/kg, and 11 rabbits (group 1) were treated with paraffin alone and served as controls. An acute mortality rate of 40% was observed in group 3 and of 68% in group 2. Surviving animals were studied for 10 days. In these animals a marked decrease in circulating granulocytes and a progressive decline in arterial PO2 were recorded (PO2 on day 10 in group 2 animals was 51.94 +/- 4.26, p less than 0.01). Microscopic and ultrastructural evaluation revealed sequestration of granulocytes in the pulmonary microvasculature. Studies of lung homogenates demonstrated increased levels of lipid peroxide derivative malondialdehyde (group 2 rabbits, 1624 +/- 638; group 1, 795 +/- 57 pm/mg pt, p less than .001) and decreased levels of the tissue antioxidant alpha-tocopherol. The results of this study are compatible with the hypothesis of leukocyte-mediated injury through production of oxygen radicals.

Animals↗
PubMed1990

Cloning and characterization of a Drosophila serotonin receptor that activates adenylate cyclase.

Using a strategy based on nucleotide sequence homology between genes encoding receptors that interact with guanine nucleotide-binding proteins, we have isolated Drosophila genomic and cDNA clones encoding a functional serotonin receptor (5HT-dro receptor). This protein is expressed predominantly in Drosophila heads and exhibits highest homology with the human 5HT1A receptor. The predicted structure of the 5HT-dro receptor reveals two unusual features: (i) eight putative transmembrane domains instead of the expected seven and (ii) a Gly-Ser repeat that is a potential glycosaminoglycan attachment site. When stably introduced into mouse NIH 3T3 cells, the 5HT-dro receptor activates adenylate cyclase in response to serotonin and is inhibited by serotonin receptor antagonists such as dihydroergocryptine. The 5HT-dro receptor or closely related receptors might be responsible for the serotonin-sensitive cyclase that has been suggested to play a role in learning and modulation of circadian rhythm in a number of invertebrate systems.

Adenylyl Cyclases↗
PubMed1989

Transgenic mice with inducible dwarfism.

The pituitary gland, composed of the anterior, intermediate and posterior lobe, represents a principal regulatory interface through which the central nervous system controls body physiology. The ontogeny of the growth hormone (GH) and prolactin (Prl) producing cells of the anterior pituitary has been analysed in transgenic mice, using the thymidine kinase obliteration system (TKO). Cells expressing the herpes virus 1 thymidine kinase (HSV1-TK) gene acquire pharmacological sensitivity to synthetic nucleosides such as FIAU (1-(2-deoxy-2-fluoro-beta-delta-arabinofuranosyl)-5-iodouracil), whose metabolites kill dividing cells. Consequently we created transgenic mice carrying the HSV1-TK gene under the control of either the rat growth hormone or the rat prolactin promoter. If transgenic mice expressing HSV1-TK in somatotropes (GH-producing cells) are treated with FIAU, they develop as dwarfs. The anterior pituitary in these animals is nearly devoid of both somatotropes and lactotropes (Prl-producing cells). By contrast, transgenic mice expressing HSV1-TK in the lactotropes, treated with FIAU, have anatomically and histologically normal pituitaries. Because toxicity depends on cell division, we conclude that Prl expression and lactotrope differentiation are post-mitotic events. These results indicate that both somatotropes and lactotropes derive from a common GH-expressing stem-somatotrope. Unexpectedly, the stemsomatotrope is still present in the adult animal and is capable of repopulating the pituitaries of treated animals with mature GH and Prl producing cells.

Animals↗
PubMed1989

Thymidine kinase obliteration: creation of transgenic mice with controlled immune deficiency.

The cell-specific expression of herpes simplex virus 1 thymidine kinase (HSV-1-tk) has provided a simple and highly efficient technique to achieve conditional ablation of targeted cell types in transgenic mice. The ablation is induced by treating transgenic animals expressing HSV-1-tk with the antiherpetic drug ganciclovir. In lymphoid tissues of mice expressing HSV-1-tk from an immunoglobulin promoter, administration of ganciclovir leads to massive destruction of B- and T-cell lineages. Tissues not expressing HSV-1-tk are insensitive to drug treatment. After depletion of greater than 99% of total thymocytes, a number of progenitor cells remain that are able to repopulate all T-cell lineages within 7 days. The ability to control and direct ablation allows for creation of conditional mutant phenotypes at precise periods of development. This technique also provides a potential means to enrich stem cell populations as well as permitting the creation of animal models for particular pathological conditions.

Acyclovir↗
PubMed1988

Targeting of an inducible toxic phenotype in animal cells.

We have developed a toxic, or suicide, vector whose action is based on the targeted expression of the herpes simplex virus 1 thymidine kinase gene product in cultured cells or transgenic animals. This protein is able to convert nucleoside analogs such as acyclovir and 1-(2-deoxy-2-fluoro-beta-D-arabino-furanosyl)-5-iodouracil (FIAU) to toxic intermediates. The activation of these compounds disrupts cellular DNA replication, leading to rapid cell death. Neither acyclovir, FIAU, nor the herpes thymidine kinase alone is harmful to cells. This approach is simple and should have widespread applicability in studying lineage formation in cultured cells and transgenic animals.

Acyclovir↗
PubMed1988

Early diagnosis of adult respiratory distress syndrome: an experimental model of complement-mediated pulmonary injury.

This article presents an experimental model of pulmonary injury resembling subclinical human adult respiratory distress syndrome (ARDS) mediated by leukocytes. The activation of complement was prolonged by an intraperitoneal injection of a suspension of zymosan in paraffin. The first step in the development of the disease was an accumulation of polymorphonuclear leukocytes in the lungs. No significant changes were observed on chest radiographs or computed tomograms and the pathophysiologic changes were only minimal in spite of the characteristic structural changes. The criteria currently used for the diagnosis of ARDS are not sensitive enough to detect the subclinical phase of the disease.

Animals↗
PubMed1987

Promoter trans-activation of protooncogenes c-fos and c-myc, but not c-Ha-ras, by products of adenovirus early region 1A.

The E1A (early region 1A) oncogene products of adenovirus type 2 trans-activate the other early viral transcription units, as well as some cellular promoters. Using a short-term cotransfection assay in murine NIH 3T3 fibroblasts, we show that c-fos and c-myc promoter activities are stimulated by the E1A proteins, whereas c-Ha-ras transcription is not affected. The product of E1A 13S mRNA is responsible for the trans-activation, whereas the 12S mRNA product has no effect. Analysis of the c-fos promoter sequences required for the E1A stimulation shows that responsive sequences are located between positions -402 and -240 upstream of the transcription initiation site. This same region also contains the c-fos serum-responsive element. Furthermore, transcription of the endogenous c-fos gene in HeLa cells is increased after E1A transfection.

Adenovirus Early Proteins↗
PubMed1986

The immunoglobulin heavy chain enhancer is stimulated by the adenovirus type 2 E1A products in mouse fibroblasts.

In contrast with our previous results (Hen, R., Borrelli, E. & Chambon, P. (1985) Science 230, 1391-1394), which demonstrated that the mouse immunoglobulin heavy chain transcriptional enhancer is repressed in lymphoid cells by the products of the adenovirus type 2 E1A transcription unit, we show here that these products activate the same enhancer in mouse fibroblast L cell lines that contain stably integrated copies of a recombinant in which the enhancer is inserted upstream from the chicken conalbumin promoter. In addition, competition experiments suggest that the activity of the heavy chain enhancer may be repressed by a trans-acting factor in mouse L cells. We speculate that the E1A products may prevent the action of this cellular repressor in these cells.

Adenovirus Early Proteins↗
PubMed1985

Repression of the immunoglobulin heavy chain enhancer by the adenovirus-2 E1A products.

The products of the adenovirus-2 (Ad2) immortalizing oncogene E1A repress the activity of the SV40, polyoma virus and E1A enhancers. Evidence is presented that Ad2 infection of MPC11 plasmocytoma cells results in an inhibition of transcription of both the gamma 2b heavy chain (IgH) and the kappa light chain immunoglobulin genes. This inhibition is caused by the Ad2 E1A products. Furthermore, the Ad2 E1A products repress transcription activated by the immunoglobulin heavy chain enhancer in chimeric recombinants, which are either stably integrated in the genome of lymphoid cells or are present as episomes. The implications of negative regulation of cellular enhancers are discussed.

Adenoviruses, Human↗
PubMed1983

Far upstream sequences are required for efficient transcription from the adenovirus-2 E1A transcription unit.

We have investigated the requirement for sequences located upstream from the TATA box for efficient transcription from the Adenovirus-2 (Ad2) E1A promoter. A series of deletions located within the E1A promoter upstream sequences were introduced into recombinants which contain or do not contain the E1A structural sequences. The amount of E1A-specific RNA produced after transfection into HeLa cells was determined by quantitative S1 nuclease analysis. We demonstrate that sequences located more than 231 bp upstream from the E1A capsite are required for efficient transcription from the E1A promoter. However, the requirement for these stimulatory sequences is less pronounced in recombinants which contain the E1A structural sequences than in those in which these sequences have been deleted. We demonstrate also that these Ad2 stimulatory sequences activate transcription in cis when inserted upstream from the heterologous -34 to +33 Ad2 major late promoter (Ad2MLP) element which is otherwise inactive when transfected into HeLa cells. These results suggest that the 270 bp Ad2 left-terminal segment contains an enhancer-like element.

Adenoviruses, Human↗
PubMed1983

An enhancer element is located 340 base pairs upstream from the adenovirus-2 E1A capsite.

A chimeric recombinant, containing the 270 bp left-terminal fragment of Adenovirus-2 (Ad2) inserted upstream from the -34 to +33 Ad2 major late promoter (Ad2MLP) element, has been used to characterize the transcription stimulatory element which is located at least 231 bp upstream from the E1A capsite in the left-end of Ad2 (Ref. 1). We demonstrate that this element, which acts in cis, possesses several properties characteristic of transcriptional enhancers. Firstly, it potentiates initiation of transcription from the capsite of the heterologous Ad2MLP and from "cryptic" sites often preceded by TATA box-like sequences. Secondly, although there is no critical distance requirement between the enhancer element and the Ad2MLP, the extent of stimulation decreases as the distance between the two element increases. However, in contrast to the other known viral or cellular enhancers which are bidirectional, the Ad2 enhancer is unidirectional, i.e. it potentiates the Ad2MLP element only when it is inserted in its "natural" orientation with respect to the direction of transcription. Using two convergent series of deletions, we have localized the Ad2 enhancer element within a 24 bp segment located at approximately 160 bp from the Ad2 left-end, i.e. 340 bp upstream from the E1A capsite. This 24 bp segment contains a sequence which exhibits a striking homology with the consensus sequence of several viral and cellular enhancers.

Adenoviruses, Human↗
PubMed1982

Immunocytology of carbonic anhydrase II in the central nervous system of jimpy mutant mice.

In agreement with previous observations in rats, carbonic anhydrase II (CAII) demonstrated immunocytochemically with a specific immune serum, is exclusively localized in oligodendrocytes in the central nervous system of both normal and dysmyelinating Jimpy mutant mice. In spite of the lack of myelin, the CAII-containing cells in Jimpy mice are abundant. These data suggest that oligodendrocytes are formed in Jimpy mice but they are not able to reach an advanced stage of maturation as defined by their capacity for producing myelin.

Animals↗