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Biomedical subjects

I Gozes

Publications and source records attributed to I Gozes.

At least 127 records · Page 7Linked to original sources
PubMed1987

The gene encoding vasoactive intestinal peptide is located on human chromosome 6p21----6qter.

Vasoactive intestinal peptide (VIP) is a regulatory neuropeptide involved in a wide variety of functions, among them vasodilation, smooth muscle relaxation, sweat secretion, gastrointestinal peristalsis, and pancreatic function. A deficient VIP-innervation of sweat glands was recently described as a possible pathogenic factor in sweating of cystic fibrosis (CF) patients. To investigate a possible role for a defective VIP-gene in cystic fibrosis, we have used a panel of rodent-human hybrid cells, retaining defined complements of human chromosomes to localize the VIP-gene to the human chromosome region 6p21----6qter. As the CF gene was recently mapped to chromosome 7, we conclude that the VIP-gene is not the primary gene defect in this disease.

Animals↗
PubMed1987

Sequential expression in the nervous system of c-myb and VIP genes, located in human chromosomal region 6q24.

Vasoactive intestinal peptide (VIP) is a major neuropeptide involved in multiple functions such as vasodilation, smooth-muscle relaxation, sweat secretion, gastrointestinal peristalsis, pancreatic function, and brain activity. In view of the multiple roles associated with VIP, it is important to understand its gene regulation. We have recently isolated the human VIP gene and determined its structure. By in situ hybridization techniques we have now localized this gene to the long arm of chromosome 6, 6q24, a chromosomal region that has been shown previously to contain the coding sequences for the nuclear protooncogene c-myb. Genes found in close proximity to each other on the chromosome are often functionally related and, as VIP is primarily expressed in the nervous system, we investigated the possible correlation of c-myb to VIP in neuronal tissue. A sharp peak of c-myb mRNA was observed in the hippocampus of 3-day-old rats, preceding the peak of VIP mRNA that occurs in this brain area at 8 days of age. Thus, the protooncogene c-myb may be associated with events in brain development occurring prior to the appearance of elevated concentrations of VIP.

Animals↗
PubMed1987

Developmental expression of the VIP-gene in brain and intestine.

Vasoactive intestinal peptide (VIP) is a major regulatory peptide in the nervous system, playing a role in normal brain activity. VIP levels change dramatically during postnatal rat brain development, raising the question of how these changes are regulated. To study VIP-gene expression, a sensitive RNA detection assay which uses in vitro-transcribed RNA hybridization probes, corresponding to 4 exons of the VIP-gene, was adapted. Results show that the major VIP-mRNA was 2000-2100 bases long in the rat. The amounts of this RNA varied markedly with development. In the frontal cortex of the rat brain, the 2000-2100-base mRNA increased by at least 5-fold from birth to 3-4 days, showing a maximal content at 14-16 days. VIP-mRNA synthesis therefore apparently precedes peptide synthesis by several days, as VIP in the rat cortex begins to increase only at about 7 days of age. Similarly, in the parietal cortex, VIP-mRNA was detected by 3 days of age. However, the increase in the mRNA content from 3 to 14 days of age was greater than in the frontal cortex, while almost no VIP-mRNA was detected in the newborn rat parietal cortex. In contrast, the hypothalamus and intestine contained significant quantities of VIP-mRNA at birth, the hypothalamic levels in newborns being much higher than anticipated from the peptide levels. In the hippocampus, the major peak in VIP-mRNA content occurred at 8 days of age. Taken together, these results indicate local controls of VIP-gene expression and a developmentally associated role for VIP-gene products. As the VIP-mRNA levels did not always parallel the peptide levels, regulation at the post-transcriptional stage may be essential for normal VIP function.

Animals↗
PubMed1987

Vasoactive intestinal peptide gene: putative mechanism of information storage at the RNA level.

The human gene coding for vasoactive intestinal peptide was recently isolated and shown to contain seven exons. We now demonstrate that an intron-containing precursor RNA can be the major vasoactive intestinal peptide-related RNA in the cell, which is in contrast to most known genes. By RNA blot analysis using a variety of genomic and cDNA-related probes we show that in a human tumor producing vasoactive intestinal peptide, most of the RNA encoding the peptide is of the precursor type. Similar precursor transcripts were found in total rat brain RNA as well. A proof of the identity of the intron-containing RNA, cDNA clones corresponding to this RNA sequence have been isolated.

Animals↗
PubMed1986

Structure and expression of the vasoactive intestinal peptide (VIP) gene in a human tumor.

To identify the VIP biosynthetic pathways, we have isolated the human VIP gene, using synthetic oligodeoxynucleotides. These specific hybridization probes were constructed according to the neuroblastoma VIP-cDNA sequence and contained up to 39 bases. The gene structure was deduced by direct chemical nucleotide sequencing. Six exons were thus far discovered; among them two short exons, one encoding VIP and the second encoding PHM-27 (a peptide having a N-terminal histidine and C-terminal methionine amide, closely related in sequence and activity to VIP). As a model system for VIP gene expression, we used a human buccal tumor producing elevated amounts of VIP. In these cells, a major transcript of the VIP-gene was identified as a long RNA containing intron sequences. The occurrence of elevated quantities of a high molecular weight, intron containing, gene transcript which is not processed directly into mature RNA suggests that VIP gene expression may be regulated at the RNA processing level.

Base Sequence↗
PubMed1986

Hypothalamic vasoactive intestinal peptide messenger ribonucleic acid is increased in lactating rats.

Vasoactive intestinal peptide (VIP) has been proposed as an inducer of PRL release. Moreover, immunocytochemical studies suggested an increase in the VIP content in the hypothalamus of lactating rats. We investigated whether this increase is regulated at the level of gene transcription. A sensitive RNA detection assay that uses in vitro transcribed RNA probes corresponding to specific exons of the VIP gene was devised to study VIP gene expression. Using this method, an approximately 2000-base long RNA containing the coding sequences for VIP was detected in rat hypothalamus. This RNA also contains the coding sequences for the VIP-related peptide PHM/I (peptide histidine methionine amide or isoleucine amide). An identical VIP-encoding RNA was previously identified in the rat cerebral cortex. A 2-fold increase was observed in hypothalamic VIP mRNA during lactation. In addition, the levels of this mRNA increased in the hypothalamus at the time of sexual maturation. Taken together, our results suggest a physiological regulation of VIP gene expression associated with its potential role as a neuroendocrine hormone.

Animals↗
PubMed1986

Detection of vasoactive intestinal peptide-encoding messenger ribonucleic acid in the rat ovaries.

Vasoactive intestinal peptide (VIP) has recently been detected in rat ovaries and has been shown to stimulate steroidogenesis by cultured rat granulosa cells. In this study we investigated whether the VIP-messenger RNA (mRNA) can be detected in the ovaries, thus suggesting local synthesis of the peptide. To study VIP-gene expression, a sensitive RNA detection assay which uses in vitro transcribed RNA probes corresponding to specific exons of the VIP gene was developed. Using this method, an approximately 2000-base RNA band containing the coding sequences for VIP was detected in rat ovaries. This RNA also contains the coding sequences for the VIP-related peptide (peptide-histidine-methionine). An identical VIP-encoding RNA was previously identified in the rat cerebral cortex. However, the VIP-mRNA quantity in the cortex was 12-fold-higher as compared to the ovaries. These results may reflect the differences in VIP concentration in the two organs. The finding of VIP-encoding mRNA in the rat ovaries suggests a local synthesis of VIP in the ovaries.

Animals↗
PubMed1985

High levels of vasoactive intestinal peptide in human milk.

The presence of immunoreactive vasoactive intestinal peptide (VIP) in human milk has been demonstrated by high performance liquid chromatography and a specific radioimmunoassay. Immunoreactive VIP-like peptide co-eluted with the synthetic marker on a reversed phase C18 column. The levels of the neuropeptide ranged between 67 and 161 pg VIP/ml milk.

Animals↗
PubMed1985

Coding sequences for vasoactive intestinal peptide and PHM-27 peptide are located on two adjacent exons in the human genome.

The human precursor gene for vasoactive intestinal peptide (VIP) and PHM-27, a peptide that has an NH2-terminal histidine and COOH-terminal methionine amide and is closely related in sequence and activity to VIP, was detected with synthetic oligodeoxynucleotide probes. These specific hybridization segments were constructed according to the neuroblastoma VIP cDNA sequence and contained up to 39 bases. The gene structure was partly deduced by hybridization to synthetic oligodeoxynucleotide probes and partly by direct chemical nucleotide sequencing. Four exons were discovered thus far; among them are two short exons separated by a 0.75-kilobase DNA stretch, one encoding PHM-27 and the second encoding VIP (exons 1 and 2). Each of these two exons encodes both the hormone amino acid residues as well as the post-translational processing signal sequences. The 3' splice sites of the two exons contain an identical stretch of nine nucleotides. At the cDNA level, the 3' splice sites contain the same stretch of six nucleotides, which are identically spliced. The occurrence of VIP and PHM-27 coding sequences on two separate exons of the human genome and the homology of their 3' splice site may allow alternative RNA processing as discussed below.

Amino Acid Sequence↗
PubMed1984

Detection of mRNAs containing regulatory peptide coding sequences using synthetic oligodeoxynucleotides.

To understand the regulation of the production of peptide hormones, it is vital to elucidate their biosynthetic pathways. We chose to study a major regulatory peptide, vasoactive intestinal peptide (VIP), a peptide possessing both neurotransmitter and neurohormone actions. To identify the specific peptide mRNA we are using, as hybridization probes, radiolabeled synthetic oligodeoxynucleotides with sequence complementary to the predicted peptide mRNA sequence. Employing this approach, we identified and partially purified a approximately 1600-base long mRNA containing VIP related sequences which can be translated in vitro into VIP-immunoreactive polypeptides. Such mRNA was detected in normal VIP producing tissue (rat brain), as well as in a tumor producing VIP (human buccal tumor). This mRNA differs in size from a known VIP-mRNA identified in human neuro-blastoma cells, suggesting the possibility of different VIP-mRNAs in different cell types.

Animals↗
PubMed1983

A possible high molecular weight precursor to vasoactive intestinal polypeptide sequestered into pheochromocytoma chromaffin granules.

Chromaffin granules, the catecholamine storage granules of pheochromocytoma were isolated from five human pheochromocytoma tumors. Vasoactive intestinal polypeptide (VIP) immunoreactivity was detected in all chromaffin granule preparations, paralleling the synthetic VIP antibody binding curve over a range of serial dilutions. In addition, gel filtration revealed an immunoreactive peptide peak coeluting with VIP. However, high molecular weight immunoreactive material was also detected on the column. This high molecular weight material was further characterized by sodium dodecyl sulfate gel electrophoresis, followed by electroblotting onto nitrocellulose paper and detection by anti-VIP antibodies with a secondary antibody conjugated to horseradish peroxidase. A 70 000 dalton immunoreactive band was identified, in which reactivity with anti-VIP antibody was inhibited by VIP; this band did not cross react with non-related antibodies. This 70 000 dalton protein may be an intermediate molecule in the biosynthesis and processing of VIP.

Adrenal Gland Neoplasms↗
PubMed1983

Monoclonal antibodies against vasoactive intestinal polypeptide: studies of structure and related antigens.

Hybridomas secreting monoclonal anti-vasoactive intestinal polypeptide (VIP) antibodies were constructed from spleen cells sensitized to VIP in vitro. The secreted antibodies were characterized by binding to VIP in indirect radioimmunoassays and enzyme-linked immunosorbent assays. Two monoclonal antibodies, characterized for their binding activities with synthetic fragments of VIP, were found to bind different sites on the VIP molecule. These monoclonal antibodies may recognize tertiary structures of the VIP. A search was conducted for antigens recognized by the monoclonal antibodies in brain: brain proteins separated on polyacrylamide gels were electroblotted onto nitrocellulose filters and were reacted first with the mouse antibody and then with goat anti-mouse immunoglobulin coupled to horseradish peroxidase as a means of detection. The monoclonal antibodies were found to react with a protein of molecular weight 60,000, which was also recognized by polyclonal antibodies, although the latter reacted with a number of additional proteins. The relationship of the protein of molecular weight 60,000 to VIP is discussed.

Adrenal Gland Neoplasms↗
PubMed1982

Conditioned media from activated lymphocytes maintain sympathetic neurons in culture.

Nerve growth factor (NGF) is vital for the development and maintenance of sympathetic neurons. In the present report, we demonstrate that NGF maintenance activity can be substituted by lymphoid cells. Indeed, coculturing lymphoid cells with sympathetic neurons in the absence of exogenous NGF resulted in neuronal survival, as measured by morphological and biochemical criteria. In addition, conditioned media from concanavalin A-activated lymphoid cells could replace NGF. The lymphoid secreted factor differs from NGF in its inability to induce neuronal differentiation, and in its lack of cross-reactivity with NGF in radioimmunoassays. We thus discovered a potential novel source for a factor essential for neuronal survival.

Animals↗
PubMed1982

Monoclonal antibodies that recognize discrete forms of tubulin.

Anti-tubulin antibodies secreted by plasmacytoma NSI-spleen cell hybrids were detected by an indirect binding assay. Different antibodies bound to different combinations of the tubulins as resolved by isoelectric focusing. Two monoclonal antibodies (TUB 2.1 and TUB 2.5) labeled only (i) the tubulin band on a polyacrylamide electropherogram and (ii) beta-tubulins as resolved by isoelectric focusing. The fraction that was specifically bound and eluted from antibody affinity columns was enriched in beta-tubulins as compared with alpha-tubulins, suggesting the possibility of some soluble tubulin homodimers and alpha,beta-heterodimers. Double labeling experiments were used to show that all detectable microtubules contained beta-tubulin.

Animals↗
PubMed1981

Protein synthesis in rat brain microvessels decreases with aging.

The synthesis of protein by brain microvessels prepared from rats 4, 15, and 21 months of age was examined in organ culture. The rate of [35S]methionine incorporation into trichloroacetic acid-insoluble protein was lower in the vessels from older animals. These decreases were not dependent on the concentration of added methionine. Differences in protein synthesis could not be accounted for by specific peptidases in the incubation mixture. Polypeptide bands corresponding to actin and to the heavy and light chains of myosin were observed among the newly synthesized proteins following electrophoresis and autoradiography of the incubation mixture on polyacrylamide gels. The pattern of proteins synthesized, however, did not appear to vary significantly between young and old animals. Age-related decreases in the synthesis of vascular proteins may contribute, in part, to some of the changes in the mechanical and functional properties of blood vessels during aging.

Aging↗
PubMed1980

The characterization and phosphorylation of an actin-like protein in synaptosomal membranes.

A protein of 43,000 daltons, named protein 'C', is a component of synaptosomal plasma membranes, vesicular and microsomal membranes, as well as synaptosomal and cellular cytoplasm. Protein 'C' undergoes endogeneous phosphorylation in synaptosomal plasma membranes but not in other subcellular fractions. This phosphorylation is stimulated by papaverine and calcium, inhibited by magnesium and not affected by cyclic nucleotides. Protein 'C' and muscle actin were shown to be very similar by isoelectric focusing, two dimensional gel electrophoresis, and by peptide mapping. This suggests that protein 'C' is an actin-like protein which undergoes endogenous phosphorylation specifically in synaptosomal plasma membranes. Phosphorylation of protein 'C' may be involved in neurotransmitter release.

Actins↗